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.

Example Input: Problem: subtracting 3 % of a from a is equivalent to multiplying a by how much ?
Options: a. 0.97, b. 9.4, c. 0.094, d. 94, e. none
Example Output: a

Example Input: Problem: at the wholesale store you can buy an 8 - pack of hot dogs for $ 1.55, a 20 - pack for $ 3.05, and a 250 - pack for $ 22.95. what is the greatest number of hot dogs you can buy at this store with $ 205 ?
Options: a. 1,108, b. 2,100, c. 2,140, d. 2,124, e. 2,256
Example Output: c

Example Input: Problem: we invested a total of $ 1,000. we invested one part of the money at 3 % and the rest of the money at 6 %. the total investment with interest at the end of the year was $ 1, 052.50. how much money did we invest at 3 % ?
Options: a. $ 160, b. $ 190, c. $ 220, d. $ 250, e. $ 280
Example Output:
d