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 man ' s speed with the current is 18 km / hr and the speed of the current is 2.5 km / hr. the man ' s speed against the current is ?
Options: a. 10, b. 18, c. 50, d. 30, e. 40
b

Problem: how many positive integer solutions does the equation 8 x + 2 y = 100 have ?
Options: a. 50, b. 84, c. 16, d. 35, e. 14
b

Problem: a statue is being carved by a sculptor. the original piece of marble weighed 250 kg. in the first week 30 percent is cut away. in the second week 20 percent of the remainder is cut away. in the third week the statue is completed when 25 percent of the remainder is cut away. what is the weight of the final statue ?
Options: a. 105 kg, b. 103 kg, c. 108 kg, d. 125 kg, e. 117 kg

a