I need to write a code for quiz input, and I honestly have no idea what I'm doing right now. Can someone write it for me and explain every step?

a. When the button is clicked, the following should happen.
a.i. Get the input from the user from an InputBox.
a.ii. While the input is something other than an A, B, C, D or Q, you should prompt the user again for input.
a.iii. If the input is an A, B, C, D, you should set the input to a character variable to hold the user’s answer choice and display the choice in a MessageBox, then the program should close.
a.iv. If the input is a Q, the program should close.