How to review the answers of the users ?

Question

Hi programmers
I am developing a standalone application that is used to conduct objective type exam.
The problem is as follow:
Suppose a student is giving a exam of 10 questions and while attempting the exam he/ she can navigate the questions.
Initially if he chooses 1st question's answer and goes to next and suppose he thinks that answer to 1st question is wrong and he goes to 1st question by clicking previous button and changes the answer.
When he/She is done with the exam and when they click on the end exam button i want that whatever they should get a review of attempted questions and there answers .
For reference i am using a Forms:
Form
---->It has a multiline textbox which is used to display the question from the database.
----> It has a groupbox control which contain 4 radiobuttons to display the choices to users.
-----> It has 3 buttons named as follow:
1. Previous: to go back to previous question.
2. Next: To move to next question.
3. End Exam: To finish the exam.

Now as i am using Microsoft Sql Server 2005 for storing questions and answers.

How this can be done.