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: last year elaine spent 20 % of her annual earnings on rent. this year she earned 35 % more than last year and she spent 30 % of her annual earnings on rent. the amount she spent on rent this year is what percent of the amount spent on rent last year ?
Options: a. 202.5, b. 194.5, c. 197.5, d. 182.5, e. 177.5
[A]: a


[Q]: Problem: by selling 15 pencils for a rupee a man loses 20 %. how many for a rupee should he sell in order to gain 20 % ?
Options: a. 8, b. 7, c. 6, d. 4, e. 10
[A]: e


[Q]: Problem: a can do a work in 15 days b in 14 days and c in 16 days. if they work on it together then in how many days required to complete the work ?
Options: a. 3360 / 210, b. 3360 / 21, c. 3360 / 674, d. 3360 / 240, e. 3360 / 224
[A]:
c


