A network designer asked you how many subnet (S) bits does he need to create 5 subnets?

(A) 2
(B) 3
(C) 4
(D) 5

3 bits are enough to create 5 subnets. You need to follow the formula of 2S > number of subnets to find out the required number of subnet bits to create 5 subnets.
*S = number of subnet bits

For example:
2^1 = 2 < 5 is not large enough
2^2 = 4 < 5 is not large enough
2^3 = 8 > 5 is enough