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 certain rectangular window is ( 1 / 3 ) times as long as it is wide. if its perimeter is 28 feet, what are its dimensions in terms of length by width ?
Options: ['a. 12 by 2', 'b. 11 by 3', 'c. 10.5 by 3.5', 'd. 10 by 4', 'e. 9 by 3']
A:
c