How do i calculate the score in this code? I probably need to use the for loop. Thanks

// Questions
var questions = [
    'What do chickens think we taste like?',
    'Before they invented drawing boards, what did they go back to?',
    'What do sheep count when they can\'t sleep?',
    'Where in the world is Carmen Sandiego?'
];
var possibleAnswers = [
    ['Humans', 'Cats', 'Pumpkins', 'Corn'],
    ['Pen and Paper', 'Stone and Chizle', 'Cave paintings', 'Sand sculptures' ],
    ['Blades of Grass', 'Lobsters', 'Car headlights', 'Humans in underware'],
    ['Paris', 'Costa Rico', 'Cuba', 'Hong Kong']
];
var correctAnswers = [ 0, 1, 0, 3 ];
var currentQuestion = 0;

// Question Areas
var input = '<label class="col-xs-6"> <input type="radio" name="answer" value="1" /> <span>Answer</span> </label>';
var questionDisplay = $('#questionDisplay');
var possibleAnswerArea = $('#possibleAnswersArea');
var finalButton = $('#finalAnswer');

// User Information
var userName = prompt('Enter Your Name');
$('#userName').text(userName);
var currentScore = 0;
var passScore = 10;
var userScore = $('#userScore').text(currentScore);

var messageArea = $('#messageArea');

var globalIndex = -1;

nextQuestion();
nextAnswer();

function checkAnswer() {
    if (globalIndex < questions.length - 1 ) {
        nextQuestion();
        nextAnswer();
        foundMatchingBlocks();
    } else {
        gameOver();
    }
    return false;
}

function nextQuestion() {
    globalIndex++;
    questionDisplay.text(questions[globalIndex]);
    }

function nextAnswer() {
    var button = '';
    for (var i = 0; i < possibleAnswers[globalIndex].length; i++){
    button += '<label class="col-xs-6"> <input type="radio" name="answer" value="0" /> <span>' + possibleAnswers[globalIndex][i] + '</span> </label>';  
    } possibleAnswerArea.html(button);
    console.log (button);

}

function gameOver() {
    alert('All out of questions');
}