A={2, 4, 6, 8, 10} is given. How many subsets of A contain 4

We are looking for subsets of A that will include 4 and 6 but not 10
Subset 1 = {4, 6}
Subset 2 = {2, 4, 6}
Subset 3 = {2, 4, 6, 8}
Subset 4 = {2, 8}
So, from the superset A, there are 4 possible subsets containing 4 and 6 but not 10

Answer = option A

=>

Subsets of A must contain 4 and 6, but must not contain 10.
These subsets either contain 2, or don’t contain 2. They also either contain 8, or don’t contain 8. There are two possible outcomes for each of 2 and 8.

So, the number of subsets of A containing 4, 6 but 10 is 2^{5-3} = 2^2 = 4.

Therefore, A is the answer.
Answer: A