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 and b started a business in partnership investing rs. 20,000 and rs. 15,000 respectively. after 6 months, c joined them with rs. 20,000. whatwill be b ' s share in total profit of rs. 15,000 earned at the end of 2 years from the startingof the business ?
Options: a. s. 5,000, b. s. 4,500, c. s. 5,700, d. s. 6,500, e. s. 7,500
[A]: b

[Q]: Problem: find the maximum value of the function f ( x ) = x 5 if x is a number between - 5 and 13.
Options: a. 6, b. 7, c. 8, d. 9, e. none
[A]: c

[Q]: Problem: the average wages of a worker during a fortnight comprising 15 consecutive working days was $ 90 per day. during the first 7 days, his average wages was $ 87 per day and the average wages during the last 7 days was $ 91 per day. what was his wage on the 8 th day ?
Options: a. $ 83, b. $ 90, c. $ 92, d. $ 97, e. $ 104
[A]:
e