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 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 %

Ex Output:
a

Ex Input:
Problem: on her annual road trip to visit her family in seal beach, california, traci stopped to rest after she traveled 1 3 of the total distance and again after she traveled 1 4 of the distance remaining between her first stop and her destination. she then drove the remaining 300 miles and arrived safely at her destination. what was the total distance, in miles, from traci ' s starting point to seal beach ?
Options: a. 600, b. 300, c. 350, d. 400, e. 550

Ex Output:
a

Ex Input:
Problem: a positive number x is multiplied by 2, and this product is then divided by 4. if the positive square root of the result of these two operations equals x, what is the value of x ?
Options: a. 9 / 4, b. 3 / 2, c. 4 / 3, d. 2 / 3, e. 1 / 2

Ex Output:
a