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: a couple who own an appliance store discover that if they advertise a sales discount of 10 % on every item in the store, at the end of one month the number of total items sold increases 15 %. their gross income from sales for one month increases by what percent ?
Options: a. 1.5 %, b. 2.5 %, c. 3.5 %, d. 4.5 %, e. 5.5 %

Answer: c

Question: Problem: in what time will a train 50 m long cross an electric pole, it its speed be 360 km / hr ?
Options: a. 0.25, b. 0.5, c. 1.5, d. 2.5, e. 3.5

Answer: b

Question: Problem: an escalator moves towards the top level at the rate of 12 ft. sec and its length is 196 feet. if a person walks on the moving escalator at the rate of 2 feet per second towards the top level, how much time does he take to cover the entire length.
Options: a. 14 sec, b. 10 sec, c. 12 sec, d. 8 sec, e. 9 sec

Answer:
a