Quiz: How to disable all buttons on click

I’m working with some code from Flash Game University…

Quiz answers are created with the following code:


            answerSprites = new Sprite();
            for (var i:int=0; i<answers.length; i++) {
                var answer:String = answers*;
                var answerSprite:Sprite = new Sprite();
                var letter:String = String.fromCharCode(65+i);// A-D
                var answerField:TextField = createText(answer,answerFormat,answerSprite,0,0,450);
                var circle:Circle = new Circle();// from Library
                circle.letter.text = letter;
                answerSprite.x = 100;
                answerSprite.y = 150+i*50;
                answerSprite.addChild(circle);
                answerSprite.addEventListener(MouseEvent.CLICK,clickAnswer);// make it a button
                answerSprite.buttonMode = true;
                answerSprite.useHandCursor = true;
                // Ignore other objects (such as textfield) within MC bounding box:
                answerSprite.mouseChildren = false;
                answerSprites.addChild(answerSprite);
            }

and on mouse click the following function is called:


        // player selects an answer
        public function clickAnswer(event:MouseEvent) {
            // get selected answer text, and compare
            var selectedAnswer = event.currentTarget.getChildAt(0).text;
            if (selectedAnswer == correctAnswer) {
                numCorrect++;
                messageField = createText("Correct!",questionFormat,gameSprite,0,140,550);
            } else {
                messageField = createText("Incorrect! The correct answer was:",questionFormat,gameSprite,0,140,550);
            }
            finishQuestion();
        }

Basically, I would like to set answerSprite.buttonMode = false; when the “clickAnswer” function is called but the answerSprite var isn’t recognized within the function. How can I refer to answerSprite?