Detailed Instructions: 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.
Q: Problem: a reduction of 42 % in the price of bananas would enable a man to obtain 64 more for rs. 40, what is reduced price per dozen ?
Options: a. 2.15, b. 8.15, c. 7.15, d. 3.15, e. 1.15
A:
d