Why is my <ol> <li> not functioning properly?

function buildList(arr) { var listHTML = '<ol>'; for( var i = 0; i < arr.length; i++) { listHTML = '<li>' + arr[i] + '</li>'; } listHTML += '</ol>'; return listHTML; }

listHTML = '<li>' + arr[i] + '</li>';

listHTML += '<li>' + arr[i] + '</li>';

var quiz = [ ['What is the capital of New York', 'Albany'], ['What is the Capital of California', 'Sacramento'], ['What is the capital of New Jersey', 'Trenton'], ['What is the capital of Virginia', 'Richmond'] ];

var questionsRight = 0; 
var questionsWrong = 0; 
var correct = []; var wrong = [];

/* Don't NEED to declare the following right away, but it's good practice to go ahead and declare the variables you're going to use. Notice you don't need to assign any default value to them */ var question; var answer; var response; var html;

function print(message) { document.write(message); }

function buildList(arr) { 
var listHTML = '<ol>'; 
for( var i = 0; i < arr.length; i++) { 
listHTML += '<li>' + arr[i] + '</li>';  // The line which is corrected
 } 
listHTML += '</ol>'; 
return listHTML; 
}

for( var i = 0; i < quiz.length; i++) {
    // Get the first item from array[i] and set it as question
    question = quiz[i][0];

      // Get the second item from array[i] and set it as answer
    answer = quiz[i][1];

    // Get input from the user and set it to the response variable
    response = prompt(question);

    if (response.toLowerCase() === answer.toLowerCase()) {
        //questionsRight is initially 0. If response === answer questionsRight = 0+1
        questionsRight += 1;    
        correct.push(question);
    }
    else {
        //questionsWrong is initially 0. If response === answer questionsWrong = 0+1
        wrong.push(question);
    }
} 

html = "You got " +  questionsRight + " question(s) right.";
html += '<h2> You got these questions correct:</h2>';
html += buildList(correct);
html += '<h2> You got these questions wrong:</h2>';
html += buildList(wrong);


print(html);