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.
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Question: Problem: in a fuel station the service costs $ 1.65 per car, every liter of fuel costs 0.65 $. assuming that a company owns 12 cars and that every fuel tank contains 55 liters and they are all empty, how much money total will it cost to fuel all cars ?
Options: a. 320 $, b. 380 $, c. 420 $, d. 448.8 $, e. 480 $

Answer: d

Question: Problem: a merchant marks goods up by 80 % and then offers a discount on the marked price. the profit that the merchant makes after offering the discount is 35 %. what % discount did the merchant offer ?
Options: a. 20 %, b. 25 %, c. 30 %, d. 35 %, e. 40 %

Answer: b

Question: Problem: a trader bought a car at 20 % discount on its original price. he sold it at a 50 % increase on the price he bought it. what percent of profit did he make on the original price ?
Options: a. 17 %, b. 72 %, c. 20 %, d. 82 %, e. 16 %

Answer:
c