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.

Example Input: Problem: the shopkeeper sale, all of the prices of the items sold were different. if the price of a radio sold at the shopkeeper sale was both the 9 th highest price and the 14 th lowest price among the prices of the items sold, how many items were sold at the shopkeeper sale ?
Options: a. 23, b. 22, c. 32, d. 26, e. 17
Example Output: b

Example Input: Problem: a rope of which a calf is tied is increased from 12 m to 23 m, how much additional grassy ground shall it graze ?
Options: a. 2989, b. 2789, c. 1210, d. 1288, e. 1211
Example Output: c

Example Input: Problem: if the price of an article went up by 30 %, then by what percent should it be brought down to bring it back to its original price ?
Options: a. 25 %, b. 23 1 / 13 %, c. 16 7 / 3 %, d. 16 6 / 3 %, e. 16 2 / 3 %
Example Output:
b