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: in what time will a train 120 m long cross an electric pole, it its speed be 121 km / hr ?
Options: a. 2.5, b. 2.7, c. 2.9, d. 3.6, e. 2.1

A: d
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Q: Problem: a student travels from his house to school at 12 km / hr and reaches school 2 hours late. the next day he travels 20 km / hr and reaches school 1 hour early. what is the distance between his house and the school ?
Options: a. 90, b. 100, c. 110, d. 120, e. 130

A: a
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Q: Problem: the owner of a furniture shop charges his customer 10 % more than the cost price. if a customer paid rs. 8800 for a computer table, then what was the cost price of the computer table ?
Options: a. rs. 6725, b. rs. 6727, c. rs. 8000, d. rs. 6725, e. rs. 6728

A:
c
****