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.

Input: Consider Input: Question: By selling 12 toffees for a rupee, a man loses 20%. How many for a rupee should be sell to get a gain of 20%?

Option A: 5

Option B: 8

Option C: 10

Option D: 15

Option E: 20

Output: Option B

Input: Consider Input: Question: Car 'X' covers a distance of 385 kms in 7 hours and car 'Y' covers a distance of 715 kms in 13 hrs. What is the difference in the speed of the two cars?

Option A: 2kms/hr

Option B: 1km/hr

Option C: 3kms/hr

Option D: 5kms/hr

Option E: None of these

Output: Option E

Input: Consider Input: Question: If a and b are different values and a b = 4(a - b), then in terms of b, a equals:

Option A: b

Option B: b

Option C: b - 8b + 16

Option D: b + 2b + 1

Option E: b^2 2bb + b
Output: Option C