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: to deliver an order on time, a company has to make 25 parts a day. after making 25 parts per day for 3 days, the company started to produce 5 more parts per day, and by the last day of work 100 more parts than planned were produced. find how many parts the company made and how many days this took.
Options: a. 600, b. 500, c. 575, d. 655, e. 675
[EX A]: e

[EX Q]: Problem: solve below question 2 x + 1 = - 13
Options: a. - 8, b. - 9, c. 9, d. 8, e. - 7
[EX A]:
e