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

[Q]: Problem: if the simple interest on a certain sum of money for 6 years is one fifth of the sum, then the rate of interest per annum is
Options: a. 3.3 %, b. 7.2 %, c. 6.1 %, d. 5.0 %, e. 3.1 %
[A]: a

[Q]: Problem: the sum of two numbers is 16 and the sum of their squares is 113. find the numbers.
Options: a. 1 and 2, b. 4 and 5, c. 7 and 8, d. 2 and 3, e. 6 and 7
[A]:
c