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: x does a work in 20 days. y does the same work in 40 days. in how many days they together will do the same work ?
Options: a. 10, b. 12, c. 20, d. 30, e. 13.33
Example Output: e

Example Input: Problem: donovan and michael are racing around a circular 400 - meter track. if donovan runs each lap in 45 seconds and michael runs each lap in 36 seconds, how many laps will michael have to complete in order to pass donovan, assuming they start at the same time ?
Options: a. 8, b. 7, c. 6, d. 5, e. 9
Example Output:
d