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: the cash realised on selling a 14 % stock is rs. 109.25, brokerage being 1 / 4 % is ?
Options: a. 366, b. 106, c. 102, d. 109, e. 122
[EX A]: d

[EX Q]: 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 %
[EX A]: a

[EX Q]: Problem: if n = 2 ^ 0.15 and n ^ b = 8, b must equal
Options: a. 3 / 80, b. 3 / 5, c. 20, d. 5 / 3, e. 80 / 3
[EX A]:
c