Choose the One Alternative That Best Completes the Statement or Answers

Choose the one alternative that best completes the statement or answers the question.
-A rectangular field is to be enclosed on four sides with a fence. Fencing costs $2 per foot for two opposite sides, and $7 per foot for the other two sides. Find the dimensions of the field of area 610 ft² that would be the cheapest to enclose.

A) 13.2 ft @ $ 2 by 46.2 ft @ $ 7
B) 7.1 ft @ $ 2 by 86.4 ft @ $ 7
C) 86.4 ft @ $ 2 by 7.1 ft @ $ 7
D) 46.2 ft @ $ 2 by 13.2 ft @ $ 7