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.

Ex Input:
Problem: an assembly line produces 15 cogs per hour until an initial order of 60 cogs is completed. the speed of the assembly line is then immediately increased so that it can produce 60 cogs per hour until another 60 cogs are produced. what is the overall average output, in cogs per hour, for the assembly line during this whole time ?
Options: a. 20, b. 22, c. 24, d. 26, e. 28

Ex Output:
c


Ex Input:
Problem: of the diplomats who attended a summit conference: 20 spoke japanese, 32 did not speak russian and 20 % of the diplomats spoke neither japanese nor russian. if 10 % of the diplomats spoke both japanese and russian, then how many diplomats attended the conference ?
Options: a. 70, b. 96, c. 108, d. 120, e. 150

Ex Output:
d


Ex Input:
Problem: jerome anticipated that the webweb. com stock price would fall and sold all his webweb. com stocks for $ 5 per stock. he paid $ 10,000 tax on the revenue. a week later, jerome became convinced that the webweb. com stock price would rise, and he used the money that he had gotten from selling the webweb. com stocks to purchase them again, this time at $ 6 per stock. if jerome ended up having 7000 webweb. com stocks fewer than the number he had before selling them, how many webweb. com stocks did he have originally ?
Options: a. 10,000, b. 11,600, c. 17,000, d. 14,000, e. 16,400

Ex Output:

c