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. 8000 and rs. 12000 in a business. after 4 months, a withdraws half of his capital and 2 months later, b withdraws one - third of his capital. in what ratio should they share the profits at the end of the year ?
Options: a. 32: 99, b. 82: 31, c. 8: 15, d. 34: 89, e. 35: 21
[EX A]: c

[EX Q]: Problem: the overall age of x and y is 19 year greater than the overall age of y and z. z is how many decades younger that x ?
Options: a. 11, b. 15, c. 12, d. 19, e. 20
[EX A]: d

[EX Q]: Problem: ifaequals the sum of the even integers from 2 to 120, inclusive, andbequals the sum of the odd integers from 1 to 119, inclusive, what is the value of a - b ?
Options: a. 60, b. 10, c. 19, d. 20, e. 21
[EX A]:
a