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.

Q: Problem: a fruit - salad mixture consists of apples, peaches, and grapes in the ratio 6: 5: 4, respectively, by weight. if 60 pounds of the mixture is prepared, the mixture includes how many more pounds of apples than grapes ?
Options: a. 15, b. 12, c. 8, d. 6, e. 4

A: c
****
Q: Problem: a train running at the speed of 20 km / hr crosses a post in 10 seconds. what is the length of the train ?
Options: a. 150, b. 250, c. 415, d. 200, e. 312

A: d
****
Q: Problem: a certain experimental mathematics program was tried out in 2 classes in each of 38 elementary schools and involved 44 teachers. each of the classes had 1 teacher and each of the teachers taught at least 1, but not more than 3, of the classes. if the number of teachers who taught 3 classes is n, then the least and greatest possible values of n, respectively, are
Options: a. 0 and 13, b. 0 and 14, c. 0 and 16, d. 1 and 9, e. 2 and 8

A:
c
****