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: if x 2 + kx - 3, is divisible by ( x - 1 ), what is the value of k
Options: a. - 1, b. 1, c. 2, d. - 1, e. 0

A: c
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Q: Problem: a person buys an article at $ 600. at what price should he sell the article so as to make a profit of 8 % ?
Options: a. 670, b. 689, c. 648, d. 740, e. 889

A: c
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Q: Problem: the roof of an apartment building is rectangular and its length is 3 times longer than its width. if the area of the roof is 588 feet squared, what is the difference between the length and the width of the roof ?
Options: a. 28., b. 40., c. 42., d. 44., e. 46.

A:
a
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