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 boat having a length 8 m and breadth 2 m is floating on a lake. the boat sinks by 1 cm when a man gets on it. the mass of the man is :
Options: a. 12 kg, b. 60 kg, c. 72 kg, d. 160 kg, e. none of these

Answer: d

Question: Problem: water is leaking out from a cylinder container at the rate of 0.31 m ^ 3 per minute. after 10 minutes, the water level decreases 1 / 9 meters. what is value of the radius in meters ?
Options: a. 2, b. 3, c. 4, d. 6, e. 9

Answer: b

Question: Problem: at the beginning of a year, the owner of a jewel shop raised the price of all the jewels in his shop by x % and lowered them by x %. the price of one jewel after this up and down cycle reduced by rs. 100. the owner carried out the same procedure after a month. after this second up - down cycle, the price of that jewel was rs. 2304. find the original price of that jewel ( in rs. )
Options: a. 2500, b. 550, c. 2600, d. 2650, e. none of these

Answer:
a