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.

Problem: 1391 x 1391 = ?
Options: a. a. 1951609, b. b. 1951601, c. c. 1951602, d. d. 1951603, e. e. 1934881
e

Problem: cereal a is 10 % sugar by weight, whereas healthier but less delicious cereal b is 2 % sugar by weight. to make a delicious and healthy mixture that is 3 % sugar, what should be the ratio of cereal a to cereal b, by weight ?
Options: a. 2: 9, b. 2: 7, c. 1: 7, d. 1: 4, e. 1: 3
c

Problem: a man can do a job in 5 days. his father takes 20 days and his son finishes it in 25 days. how long will they take to complete the job if they all work together ?
Options: a. 6.3, b. 6.9, c. 3.5, d. 6.1, e. 6.2

c