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: a and b invests rs. 2500 and rs. 4000 respectively in a business. if a doubles his capital after 6 months. in what ratio should a and b divide that year ' s profit ?
Options: a. 11: 5, b. 15: 16, c. 15: 2, d. 9: 9, e. 11: 1

Output: b

Input: Consider Input: Problem: at garage sale, all of the prices of the items sold were different. if the price of a radio sold at the garage sale was both the 9 th highest price and the 35 th lowest price among the prices of the items sold, how many items were sold at the garage sale ?
Options: a. 43, b. 28, c. 44, d. 49, e. 46

Output: a

Input: Consider Input: Problem: if 1 / ( x + 4 ) + 1 / ( x - 4 ) = 1 / ( x - 4 ), what is the value of x ?
Options: a. 5, b. 4, c. 1, d. 2, e. 3
Output: b