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: the average runs scored by a batsman in 20 matches is 40. in the next 10 matches the batsman scored an average of 30 runs. find his average in all the 30 matches ?
Options: a. 31, b. 36.67, c. 88, d. 13, e. 12
[EX A]: b

[EX Q]: Problem: 54671 - 14456 - 31466 = ?
Options: a. 2449, b. 5449, c. 8749, d. 8449, e. 6468
[EX A]: c

[EX Q]: Problem: a, b and c, each working alone can complete a job in 6, 8 and 12 days respectively. if all three of them work together to complete a job and earn $ 1170, what will be b ' s share of the earnings ?
Options: a. $ 390, b. $ 520, c. $ 1080, d. $ 1170, e. $ 630
[EX A]:
a

