Correct option is C
Series: 42, 57, 72, 87, 102, ?
Logic: Each number increases by 15:
42 + 15 = 57
57 + 15 = 72
72 + 15 = 87
87 + 15 = 102
So,
102 + 15 = 117
Logic: Each number increases by 15:
42 + 15 = 57
57 + 15 = 72
72 + 15 = 87
87 + 15 = 102
So,
102 + 15 = 117
Thus, correct option is (b).