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: in one alloy there is 10 % chromium while in another alloy it is 6 %. 15 kg of the first alloy was melted together with 35 kg of the second one to form a third alloy. find the percentage of chromium in the new alloy.
Options: a. 7.2 %, b. 9 %, c. 9.2 %, d. 8.6 %, e. 8.4 %

Output: a

Input: Consider Input: Problem: ages of two persons differ by 20 years. if 6 year ago, the elder one be 3 times as old the younger one, find their present age
Options: a. 12,28, b. 14,30, c. 16,36, d. 18,34, e. 19,34

Output: c

Input: Consider Input: Problem: 1257 1275 1527................ + 7521 the addition problem above shows 4 of the 24 different integers that can be formed by using each of the digits 1, 25 and 7 exactly once in each integer. what is the sum t of the 24 integers ?
Options: a. 26996, b. 44406, c. 60444, d. 66660, e. 99990
Output: e