I am trying to design a question to test for divisibility

$n3=range(0,9,1); and students have to choose the next digit to make the number divisible by 4

if $n3 is even the students must input 0,4,8 to be true

if $n3 is odd the students must input 2 or 6 to be correct.

I am not sure how to us the if(a,b,c) in this case or if I should be using indexof....or both?  Any help would be appreciated.