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: car z travels 50 miles per gallon of gasoline when driven at a constant rate of 45 miles per hour, but travels 20 percent fewer miles per gallon of gasoline when driven at a constant rate of 60 miles per hour. how many miles does car z travel on 10 gallons of gasoline when driven at a constant rate of 60 miles per hour ?
Options: a. 320, b. 375.2, c. 400, d. 408.3, e. 440
Example Output: c

Example Input: Problem: farm tax is levied on the 45 % of the cultivated land. the tax department collected total $ 3840 through the farm tax from the village of mr. willam. mr. willam paid only $ 480 as farm tax. the percentage of total land of mr. willam over the total taxable land of the village is :
Options: a. 15 %, b. 25 %, c. 15.125 %, d. 27.78 %, e. none
Example Output: d

Example Input: Problem: after successive discounts of 20 %, 10 % and 5 % a certain good is sold for rs. 6700. find the actual price of the good.
Options: a. s. 6000, b. s. 9000, c. s. 10800, d. s. 9795, e. s. 9980
Example Output:
d