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.

[EX Q]: Problem: four bells commence tolling together and toll at intervals of 2, 4, 6, 8 seconds respectively. in 18 minutes, how many times do they toll together ?
Options: a. 43, b. 44, c. 45, d. 46, e. 47
[EX A]: c

[EX Q]: Problem: in what time will a railway train 50 m long moving at the rate of 36 kmph pass a telegraph post on its way ?
Options: a. 5 sec, b. 4 sec, c. 3 sec, d. 6 sec, e. 1 sec
[EX A]: a

[EX Q]: Problem: a teacher grades students ’ tests by subtracting twice the number of incorrect responses from the number of correct responses. if student a answers each of the 100 questions on her test and receives a score of 76, how many questions did student a answer correctly ?
Options: a. 92, b. 60, c. 73, d. 82, e. 91
[EX A]:
a