You are given a math word problem and you are supposed to make use of mathematical concepts like probability, combinatorics, linear equations, sequences/series, or simple operators like addition, subtraction, division, or multiplication to answer the given question. Choose the best option from the 5 given options and report that option.

[EX Q]: Question: man buys an article for 10% less than its value and sells it for 10% more than its value. His gain or loss percent is?

 Option A: 12

 Option B: 76

 Option C: 26

 Option D: 20

 Option E: 12
[EX A]: Option D

[EX Q]: Question: In how many seconds will a train 100 meters long pass an oak tree, if the speed of the train is 36 km/hr?

 Option A: 6

 Option B: 8

 Option C: 10

 Option D: 12

 Option E: 14
[EX A]: Option C

[EX Q]: Question: A store’s selling price of $2500 for a certain printer would yield a profit of 40 percent of the store’s cost for the printer. What selling price would yield a profit of 50 percent of the printer’s cost?

 Option A: 	$2400

 Option B: 	$2464

 Option C: 	$2650

 Option D: 	$2478

 Option E: 	$2800
[EX A]:
Option D