Quiz.prototype.guess question about parameter

I keep getting crossed up when reading the guess function. Can anyone clarify my understanding? The guess function has 1 parameter, which is argument, which is passed into the isCorrectAnswer(choice) function as an argument when we call it from the question.js file.

Where I keep getting crossed up is, why are we using answer in the guess function, and choice in the isCorrectAnswer function? Is there a reason for this? Wouldn't it make more sense to use choice for both? Or even answer for both? Since a choice is an answer, and an answer is a choice? I tried it this way and it works.

I think I'm getting crossed up because there are so many pieces to this equation, it can be mind-boggling. Any feedback is appreciated. Thanks in advance!

quiz.js file

Quiz.prototype.guess = function(choice) {
    if(this.getCurrentQuestion().isCorrectAnswer(choice)) {
        this.score++;
    }
    this.currentQuestionIndex++;
};

question.js file

Question.prototype.isCorrectAnswer = function (choice) {
    return this.answer === choice;
};