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: if a lends rs. 3150 to b at 8 % per annum and b lends the same sum to c at 12.5 % per annum then the gain of b in a period of 2 years is ?
Options: a. 280, b. 295, c. 283.5, d. 245, e. 200
[A]: c

[Q]: Problem: what least number must be subtracted from 13294 so that the remainder is exactly divisible by 97 ?
Options: a. 3, b. 5, c. 7, d. 9, e. 10
[A]: b

[Q]: Problem: in a park there are two ponds with both brown ducks and green ducks. in the smaller pond there are 45 ducks and in the larger pond there are 55 ducks. if 20 % of the ducks in the smaller pond are green and 40 % of the ducks in the larger pond are green, then what percentage of ducks are green ?
Options: a. 25 %, b. 27 %, c. 29 %, d. 31 %, e. 33 %
[A]:
d