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.
--------
Question: 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

Answer: b

Question: Problem: a clock shows the time as 9 a. m. if the minute hand gains 7 minutes every hour, how many minutes will the clock gain by 6 p. m. ?
Options: a. 30 min, b. 35 min, c. 63 min, d. 50 min, e. 55 min

Answer: c

Question: Problem: find the compound interest on $ 1200 for 6 years at 20 % p. a. if ci is component yearly ?
Options: a. $ 120, b. $ 150, c. $ 2383, d. $ 250, e. $ 300

Answer:
c