The correct option is B 60
Find: 6 + 12 + 18 + 24
First term = 6, second term = 12, third term = 18, fourth term = 24
Sum of first and fourth terms = 6 + 24 = 30
Sum of second and third terms = 12 + 18 = 30
So, 6 + 12 + 18 + 24 = 30 × 2
6 + 12 + 18 + 24 = 60