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 clock shows the time as 9 a. m. if the minute hand gains 7 minutes every hour, how many minutes will the clock gain by 6 p. m. ?
Options: a. 30 min, b. 35 min, c. 63 min, d. 50 min, e. 55 min

A: c
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Q: Problem: points a, b, c, and d, in that order, lie on a line. if ab = 3 cm, ac = 4 cm, and bd = 8 cm, what is cd, in centimeters ?
Options: a. 7, b. 2, c. 3, d. 4, e. 5

A: a
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Q: Problem: two goods trains each 500 m long are running in opposite directions on parallel tracks. their speeds are 30 km / hr and 90 km / hr respectively. find the time taken by the slower train to pass the driver of the faster one ?
Options: a. 48, b. 30, c. 26, d. 23, e. 12

A:
b
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