In reply to sai_pra99:
You are only requesting 2 bits of the number to be displayed.
'b11 = 0011 in binary → the lower 2 bits give you 3
'd11 = 1011 in binary → the lower 2 bits give you 3
'h11 = 0001_0001 in binary → the lower 2 bits give you 1
The output of "$display(2’b11,2’d11,2’h11); " should be “331”