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, b and c invested rs. 2400, rs. 7200 and rs. 9600 respectively, in a partnership business. find the share of a in profit of rs. 9000 after a year ?
Options: a. 1125, b. 2400, c. 7200, d. 2500, e. 2511
A:
a