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.

Input: Consider Input: Problem: the present worth of rs. 2310 due years hence, the rate of interest being 15 % per annum, is :
Options: a. rs. 1440, b. rs. 1750, c. rs. 1680, d. rs. 1840, e. none of these

Output: c


Input: Consider Input: Problem: if a = 105 and a ^ 3 = 21 × 25 × 45 × z, what is the value of z ?
Options: a. 35, b. 42, c. 45, d. 49, e. 54

Output: d


Input: Consider Input: Problem: working alone, printers x, y, and z can do a certain printing job, consisting of a large number of pages, in 12, 25, and 30 hours, respectively. what is the ratio of the time it takes printer x to do the job, working alone at its rate, to the time it takes printers y and z to do the job, working together at their individual rates ?
Options: a. 4 / 11, b. 1 / 2, c. 15 / 22, d. 150 / 11, e. 11 / 4


Output: d