Q: 80 ? 860 1550 2440 3530
Options:
(A) 370
(B) 840
(C) 750
(D) 860
(E) 960 Let's give some random thoughts before answering.

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
10^2 - 20 = 80
20^2 - 30 = 370
30^2 - 40 = 860
40^2 - 50 = 1550
50^2 - 60 = 2440
60^2 - 70 = 3530.
Therefore, the answer is (A).