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.

Q: Problem: what is the greatest positive integer e such that 3 ^ e is a factor of 9 ^ 10 ?
Options: a. e = 5, b. e = 9, c. e = 10, d. e = 20, e. 30

A: d
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Q: 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

A: c
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Q: Problem: a cricket player whose bowling average was 23.50 runs per wicket, takes 5 wicket for 52 runs in a match. due to this his average decreases by 0.50. what will be the number of wickets taken by him till the last match ?
Options: a. 64, b. 72, c. 131, d. 456, e. 108

A:
c
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