5,9,18,31,52,__\nOptions:\n(A) 79\n(B) 80\n(C) 86\n(D) 82\n(E) 83 Now, let's think a bit. Some random thoughts:
User
(9+5) +4 = 18\n(16+9) +6 = 31\n(28+16)+8 = 52\n(48+28)+10 = 86
The final answer: (C).
Assistant