Mitron, not always form1. You can also set a Subroutine in a module as the main bit, a different form... 
1ns0mnia, you already know how to use the timer, appactivate and sendkeys.send, so all you need is the random number, right?
Code:
Dim rand as Integer
rand = Int(rnd*3) + 1
gives a random integer from 1 to 3. Int cuts off the decimal, rnd gives a pseudo random number (based off the current time) which is between 0 and 1, multiplying by 3 means the Int(rnd*3) part can be 0, 1 or 2, and adding the one gives the possible answers being 1, 2 and 3.
Description because it's better to teach than to spoonfeed.