Solve the Problem $\$ 5$ Per Foot for Two Opposite Sides, And

Solve the problem.
-A rectangular field is to be enclosed on four sides with a fence. Fencing costs $\$ 5$ per foot for two opposite sides, and $\$ 7$ per foot for the other two sides. Find the dimensions of the field of area $870 \mathrm { ft } ^ { 2 }$ that would be the cheapest to enclose.

A) $24.9 \mathrm { ft } @ \$ 5$ by $34.9 \mathrm { ft } @ \$ 7$
B) $41.3 \mathrm { ft } @ \$ 5$ by $21.1 \mathrm { ft } @ \$ 7$
C) $34.9 \mathrm { ft } @ \$ 5$ by $24.9 \mathrm { ft } @ \$ 7$
D) $21.1 \mathrm { ft } @ \$ 5 \mathrm { by } 41.3 \mathrm { ft } @ \$ 7$