Creating a quiz game, how do I avoid code duplication in javascript?

Question

I am creating a simple game of selecting the correct answer, the basic structure is working, but I would like to improve my code, and learn to factor better.

Follows the passage that define the variables I use:

let pos = 0, test, test_status, question, choice, choices, chA, 
chB, chC, chD, chE, chF, chG, chH, chI, correct = 0, wrong = 0;

let questions = [
{
        question: "Qual dos dois filmes se refere a 'Jornada nas Estrelas'?",
        a: "Star Trek",
        b: "Star Wars",
        c: "ambas as respostas estāo corretas",
        d: "ambas as respostas estão incorretas",
        answer: "A"
},
{
        question: "A frase icônica: 'You bow to no one my friends', foi dito por qual personagem?",
        a: "Obi-Wan Kenobi",
        b: "Gandalf",
        c: "Tex Willer",
        d: "Aragorn",
        e: "Capitāo America",
        f: "Spock",
        g: "Nenhuma das opções acima",
        answer: "D"
}

And here the relevant code my question:

    question = questions[pos].question;
    chA = questions[pos].a;
    chB = questions[pos].b;
    chC = questions[pos].c;
    chD = questions[pos].d;
    chE = questions[pos].e;
    chF = questions[pos].f;
    chG = questions[pos].g;
    chH = questions[pos].h;
    chI = questions[pos].i;

    test.innerHTML = "<h3>"+question+"</h3>";

    test.innerHTML += "<label> <input type='radio' name='choices' value='A'> " + chA + "</label><br>";
    if (typeof chB !== "undefined")
        test.innerHTML += "<label> <input type='radio' name='choices' value='B'> " + chB + "</label><br>";
    if (typeof chC !== "undefined")
        test.innerHTML += "<label> <input type='radio' name='choices' value='C'> "+chC+"</label><br>";
    if (typeof chD !== "undefined")
        test.innerHTML += "<label> <input type='radio' name='choices' value='D'> " + chD + "</label><br>";
    if (typeof chE !== "undefined")
        test.innerHTML += "<label> <input type='radio' name='choices' value='E'> "+chE+"</label><br>";
    if (typeof chF !== "undefined")
        test.innerHTML += "<label> <input type='radio' name='choices' value='F'> "+chF+"</label><br>";
    if (typeof chG !== "undefined")
        test.innerHTML += "<label> <input type='radio' name='choices' value='G'> "+chG+"</label><br>";
    if (typeof chH !== "undefined")
        test.innerHTML += "<label> <input type='radio' name='choices' value='H'> "+chH+"</label><br>";
    if (typeof chI !== "undefined")
        test.innerHTML += "<label> <input type='radio' name='choices' value='I'> "+chI+"</label><br>";
    test.innerHTML += "<label></label><br>";
    test.innerHTML += "<button onclick='checkAnswer()'>Confirmar Resposta</button>";

My text editor complains of code duplication both at the initialization of variables chA, chB ... chI as in the part that creates the input element in HTML (innerHTML...). My question is, how should I proceed to eliminate this tangle of repetitive code, and put everything in a loop, for example?

One last detail: need to check every time if the variable in question is not Undefined to prevent the following from occurring:

Answer 1

    let pos = 0, test, test_status, question, choice, choices, chA, 
    chB, chC, chD, chE, chF, chG, chH, chI, correct = 0, wrong = 0;

    let questions = [
    {
            question: "Qual dos dois filmes se refere a 'Jornada nas Estrelas'?",
            a: "Star Trek",
            b: "Star Wars",
            c: "ambas as respostas estāo corretas",
            d: "ambas as respostas estão incorretas",
            answer: "a"
    },
    {
            question: "A frase icônica: 'You bow to no one my friends', foi dito por qual personagem?",
            a: "Obi-Wan Kenobi",
            b: "Gandalf",
            c: "Tex Willer",
            d: "Aragorn",
            e: "Capitāo America",
            f: "Spock",
            g: "Nenhuma das opções acima",
            answer: "d"
    }]

    let code = '';
    questions.forEach(function(v, i) {
        code += '<div data-q="'+i+'">'
        code += '<h4>'+v.question+'</h4>'
        code += ((questions[i].hasOwnProperty('a')) ? '<p><input class="quest" name="quest-'+i+'" type="radio" value="a">' +v.a + '<p>' : '');
        code += ((questions[i].hasOwnProperty('b')) ? '<p><input class="quest" name="quest-'+i+'" type="radio" value="b">' +v.b + '<p>' : '');
        code += ((questions[i].hasOwnProperty('c')) ? '<p><input class="quest" name="quest-'+i+'" type="radio" value="c">' +v.c + '<p>' : '');
        code += ((questions[i].hasOwnProperty('d')) ? '<p><input class="quest" name="quest-'+i+'" type="radio" value="d">' +v.d + '<p>' : '');
        code += ((questions[i].hasOwnProperty('e')) ? '<p><input class="quest" name="quest-'+i+'" type="radio" value="e">' +v.e + '<p>' : '');
        code += ((questions[i].hasOwnProperty('f')) ? '<p><input class="quest" name="quest-'+i+'" type="radio" value="f">' +v.f + '<p>' : '');
        code += ((questions[i].hasOwnProperty('g')) ? '<p><input class="quest" name="quest-'+i+'" type="radio" value="g">' +v.g + '<p>' : '');
        code += '</div>';
    })

let result = document.getElementById("result");
result.innerHTML = code;

<div id="result"></div>