Given a math problem with context and a question and 5 answer choices, the task is to provide the correct answer choice based on the problem. You must choose one of the given answer choices by letter: a, b, c, d, or e; anything else is invalid.

[Q]: Problem: the area of a square field is 625 km 2. how long will it take for a horse to run around at the speed of 25 km / h ?
Options: a. 12 h, b. 10 h, c. 8 h, d. 4 h, e. none of these
[A]: d


[Q]: Problem: a van takes 5 hours to cover a distance of 495 km. what speed in kph should the van maintain to cover the same distance in 3 / 2 of the previous time ?
Options: a. 60, b. 63, c. 66, d. 69, e. 72
[A]: c


[Q]: Problem: 20 percent of country y ' s yearly exports come from fruit exports. one - sixth of all fruit exports from country y are orange exports. if country y generates $ 4.25 million from its orange exports, how much money does it generate from its yearly total of exports ?
Options: a. $ 21.25 m, b. $ 25.5 m, c. $ 106.25 m, d. $ 127.5 m, e. $ 153 m
[A]:
d