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: a and b started a business investing rs. 80,000 and rs 20,000 respectively. in what ratio the profit earned after 2 years be divided between a and b respectively ?
Options: a. 4: 1, b. 3: 2, c. 18: 20, d. 18: 4, e. 17: 4
Example Output: a

Example 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
Example Output: d

Example Input: Problem: increasing the original price of a certain item by 25 percent and then increasing the new price by 30 percent is equivalent to increasing the original price by what percent ?
Options: a. 31.25, b. 37.5, c. 50.0, d. 52.5, e. 62.5
Example Output:
e