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.
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Question: Problem: mary works in a restaurant a maximum of 70 hours. for the first 20 hours, she is paid $ 8 per hour. for each overtime hour, she is paid at a rate which is 25 % higher than her regular rate. how much mary can earn in a week ?
Options: a. 600, b. 620, c. 660, d. 320, e. 400

Answer: c

Question: 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

Answer: c

Question: Problem: stacy and heather are 40 miles apart and walk towards each other along the same route. stacy walks at constant rate that is 1 mile per hour faster than heather ' s constant rate of 5 miles / hour. if heather starts her journey 24 minutes after stacy, how far from the original destination has heather walked when the two meet ?
Options: a. 4 miles, b. 8 miles, c. 17 miles, d. 6 miles, e. 12 miles

Answer:
c