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.
--------
Question: Problem: find the simple interest on rs. 72,000 at 16 2 / 3 % per year for 9 months.
Options: a. 7500, b. 6500, c. 9000, d. 9500, e. none of them

Answer: c

Question: Problem: a man can row upstream at 25 kmph and downstream at 55 kmph, and then find the speed of the man in still water ?
Options: a. 65, b. 40, c. 30, d. 78, e. 38

Answer: b

Question: Problem: in the first 10 overs of a cricket game, the run rate was only 4.2. what should be the run rate in the remaining 40 overs to reach the target of 282 runs ?
Options: a. 6.25, b. 6.5, c. 6.75, d. 7, e. 6

Answer:
e