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: if 12 machine can finish a job in 40 days, then how many more machines would be needed to finish the job in one - fourth less time ?
Options: a. a. 4, b. b. 8, c. c. 10, d. d. 12, e. e. 16

Output: a

Input: Consider Input: Problem: ravi purchased a refrigerator and a mobile phone for rs. 15000 and rs. 8000 respectively. he sold the refrigerator at a loss of 5 percent and the mobile phone at a profit of 10 percent. overall he make a.
Options: a. 50, b. 288, c. 27, d. 200, e. 881

Output: a

Input: Consider Input: Problem: the set s consists of 5 numbers: { 1, 2,3, 4,5 }. if all possible subsets including the null set are created and one subset is chosen at random, what is the probability that the subset has 3 or 4 as its largest number ?
Options: a. 3 / 4, b. 3 / 8, c. 3 / 16, d. 5 / 16, e. 3 / 32
Output: b