Choice (B) is true.
For (A): 5 is not a divisor of 14, whose only divisors are 1, 2, 7, and 14.
For (B): the factors of 10 are: 1, 2, 5, and 10. The factors of 15 are: 1, 3, 5, and 15. As we can see, the only, and greatest, common factor is 5.
For (C): 3 is not a factor of 13, which is a prime number.
For (D): again, 3 is not a factor of 14.
