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: how many prime numbers are between 29 / 3 and 87 / 6 ?
Options: a. 1, b. 2, c. 3, d. 4, e. 5
[A]: b

[Q]: Problem: a boat having a length 8 m and breadth 2 m is floating on a lake. the boat sinks by 1 cm when a man gets on it. the mass of the man is :
Options: a. 12 kg, b. 60 kg, c. 72 kg, d. 160 kg, e. none of these
[A]: d

[Q]: Problem: express a speed of 63 kmph in meters per second ?
Options: a. 10 mps, b. 14 mps, c. 17.5 mps, d. 19.4 mps, e. 10.8 mps
[A]:
c