How can i “unset” a class that has been declared

Question

I have a complete Form Creation System. There are many different Question Types and I have to check if the answer which the person had made is correct.

All types of

Answer 1

No. You have a design flaw.
You should have probably let the different type of questions inherit from one abstract question class and/or (1) used the factory pattern or (2) used the strategy pattern.