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.

Input: Consider Input: Problem: an aeroplane covers a certain distance at a speed of 150 kmph in 2 hours. to cover the same distance in 1 2 / 3 hours, it must travel at a speed of :
Options: a. 1300 kmph, b. 160 kmph, c. 180 kmph, d. 1080 kmph, e. none

Output: c


Input: Consider Input: Problem: a merchant marks goods up by 80 % and then offers a discount on the marked price. the profit that the merchant makes after offering the discount is 35 %. what % discount did the merchant offer ?
Options: a. 20 %, b. 25 %, c. 30 %, d. 35 %, e. 40 %

Output: b


Input: Consider Input: Problem: two trains travelling in the same direction at 50 and 40 kmph completely pass off another in 1 1 / 2 minute. if the length of the first train is 125 m, what is the length of the second train ?
Options: a. 300 m, b. 287 m, c. 125 m, d. 250 m, e. 167 m


Output: c