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: find the simple interest on rs. 72,000 at 16 2 / 3 % per year for 9 months.
Options: a. 7500, b. 6500, c. 9000, d. 9500, e. none of them

Output: c


Input: Consider Input: Problem: a / ( b / c. in the expression above, a, b, and c are different numbers and each is one of the numbers 2, 3, or 6. what is the largest possible value of the expression ?
Options: a. 2 / 18, b. 6 / 3, c. 30 / 2, d. 18 / 2, e. 6 / 18

Output: d


Input: Consider Input: Problem: a certain airline ' s fleet consisted of 90 type a planes at the beginning of 1980. at the end of each year, starting with 1980, the airline retired 3 of the type a planes and acquired 4 new type b plans. how many years did it take before the number of type a planes left in the airline ' s fleet was less than 50 percent of the fleet ?
Options: a. 11, b. 12, c. 13, d. 14, e. 15


Output: c