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: 54671 - 14456 - 31466 = ?
Options: a. 2449, b. 5449, c. 8749, d. 8449, e. 6468
[EX A]: c

[EX Q]: Problem: car x began traveling at an average speed of 35 miles per hour. after 72 minutes, car y began traveling at an average speed of 70 miles per hour. when both cars had traveled the same distance, both cars stopped. how many miles did car x travel from the time car y began traveling until both cars stopped ?
Options: a. 15, b. 20, c. 40, d. 42, e. 68
[EX A]: d

[EX Q]: Problem: in a family 16 people eat only vegetarian, 9 people eat only non veg., 12 people eat both veg and non veg.. how many people eat veg in the family ?
Options: a. 28, b. 26, c. 22, d. 31, e. 21
[EX A]:
a