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.

Problem: a statue is being carved by a sculptor. the original piece of marble weighed 180 kg. in the first week 28 percent is cut away. in the second week 18 percent of the remainder is cut away. in the third week the statue is completed when 20 percent of the remainder is cut away. what is the weight of the final statue ?
Options: a. 105 kg, b. 85 kg, c. 108 kg, d. 125 kg, e. 117 kg
b

Problem: a thief is spotted by a policeman from a distance of 150 meters. when the policeman starts the chase, the thief also starts running. if the speed of the thief be 8 km / hr and that of the policeman 10 km / hr, how far the thief will have run before he is overtaken ?
Options: a. 350 m, b. 200 m, c. 400 m, d. 600 m, e. none of them
d

Problem: find the average of all prime numbers between 10 and 30.
Options: a. 30, b. 33.6, c. 39.8, d. 18.6, e. none

d