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.

[EX Q]: Problem: a and b invests rs. 2500 and rs. 4000 respectively in a business. if a doubles his capital after 6 months. in what ratio should a and b divide that year ' s profit ?
Options: a. 11: 5, b. 15: 16, c. 15: 2, d. 9: 9, e. 11: 1
[EX A]: b

[EX Q]: Problem: if the wages of 6 men for 15 days be rs. 2100, then find the wages of for 12 days.
Options: a. rs. 2420, b. rs. 2500, c. rs. 2520, d. rs. 2020, e. rs. 2650
[EX A]: c

[EX Q]: Problem: what is 30 % of 80 ?
Options: a. 24, b. 66, c. 367, d. 28, e. 267
[EX A]:
a