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: by selling 15 pencils for a rupee a man loses 20 %. how many for a rupee should he sell in order to gain 20 % ?
Options: a. 8, b. 7, c. 6, d. 4, e. 10

A: e
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Q: Problem: a man traveled from the village to the post - office at the rate of 25 kmph and walked back at the rate of 4 kmph. if the whole journey took 5 hours 48 minutes, find the distance of the post - office from the village ?
Options: a. 70 m, b. 80 km, c. 20 km, d. 10 km, e. 73 km

A: c
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Q: Problem: a “ sophie germain ” prime is any positive prime number p for which 2 p + 1 is also prime. the product of all the possible units digits of sophie germain primes greater than 8 is
Options: a. 189, b. 197, c. 221, d. 227, e. 230

A:
a
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