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 no. when divided by 281 gives a remainder 160, what remainder will be obtainedby dividingthe same no. 21 ?
Options: a. 21, b. 22, c. 23, d. 24, e. 25
[A]: a

[Q]: Problem: in a certain pond, 50 fish were caught, tagged, and returned to the pond. a few days later, 50 fish were caught again, of which 5 were found to have been tagged. if the percent of tagged fish in the second catch approximates the percent of tagged fish in the pond, what is the approximate number of fish in the pond ?
Options: a. 400, b. 500, c. 1,250, d. 2,500, e. 10,000
[A]: b

[Q]: Problem: x and y are two towns. ganesh covers the distance from x to y at an average speed of 43 km / hr. however, he covers the distance from y to x at an average speed of 34 km / hr. his average speed during the whole journey in km / hr. is :
Options: a. 34, b. 43, c. 40, d. 38, e. 29
[A]:
d