For this chain-of-thought reasoning and answer, what was the question?
Speed = 63 * 5/18 = 35/2 m/sec
Time taken = 210 * 2/35 = 12 sec
 A: (D)

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.
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Q: A train 210 m long, running with a speed of 63 km/hr will pass a tree in?
Options:
(A) 18 sec
(B) 16 sec
(C) 76 sec
(D) 12 sec
(E) 17 sec