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: each of the three people individually can complete a certain job in 3, 4, and 6 hours, respectively. what is the lowest fraction of the job that can be done in 1 hour by 2 of the people working together at their respective rates ?
Options: a. 1 / 3, b. 9 / 20, c. 8 / 15, d. 5 / 12, e. 2 / 3

Output: d


Input: Consider Input: Problem: 18.05 ã — 0.001 = ?
Options: a. 0.1805, b. 0.01805, c. 1.805, d. 0.001805, e. none of these

Output: b


Input: Consider Input: Problem: the ratio of the volumes of two cubes is 125: 512. what is the ratio of their total surface areas ?
Options: a. 81: 121, b. 25: 64, c. 729: 1331, d. 27: 121, e. none of these


Output: b