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: a man bought an article and sold it at a gain of 5 %. if he had bought it at 5 % less and sold it for re 5 less, he would have made a profit of 10 %. the c. p. of the article was
Options: a. 960, b. 980, c. 900, d. 970, e. 1000

A: e
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Q: Problem: when positive integer n is divided by 7, the remainder is 1. when n is divided by 11, the remainder is 5. what is the smallest positive integer k such that k + n is a multiple of 77 ?
Options: a. 2, b. 4, c. 6, d. 8, e. 10

A: c
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Q: Problem: what is the probability of getting exactly 2 heads in a single throw of four fair coins ?
Options: a. 1 / 2, b. 3 / 4, c. 3 / 8, d. 3 / 16, e. 5 / 16

A:
c
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