C : 13
8 is not a prime number since it's dividable by multiple numbers. For example 2(4), 1(8)
6 is not a prime number since it's dividable by 3(2), 1(6)
13 is a prime number because it's only dividable by itself.
10 is not a prime number because it can be divided by 5(2), 1(10)
So only 13 matches as a prime number.