Answer:
B, 51, 60, 69
Step-by-step explanation:
15 + 9 = 24
24 + 9 = 33
33 + 9 = 42
So the next numbers should be 9 "away" from the previous number.
42 + 9 = 51
51 + 9 = 60
60 + 9 = 69
So the answer is B
