Answer:
B
Step-by-step explanation:
Two numbers are relatively prime when there is no integer greater than one that that is a factor of both of them.
A: 15 and 21 both have a factor of 3.
B: 24 and 49 have no common factors, and therefore, are relatively prime.
C. 35 and 135 both have a factor of 5.
D: 45 and 102 both have a factor of 3.
