In this task, you need to provide the correct option for a given problem from the provided options.
Q: Problem: how many two digit prime numbers are there in which both digits are prime numbers ? ( for example , 23 is one of these numbers but 31 is not , since 1 is not a prime number . )
Options: a ) 3 , b ) 4 , c ) 5 , d ) 8 , e ) 15
A:
b