Solve Each Problem $\$ 8$ Per Foot for Two Opposite Sides, And

Solve each problem.
-A rectangular field is to be enclosed on four sides with a fence. Fencing costs $\$ 8$ per foot for two opposite sides, and $\$ 4$ per foot for the other two sides. Find the dimensions of the field of area $800 \mathrm{ft}^{2}$ that would be the cheapest to enclose.

A) $40 \mathrm{ft} @ \$ 8$ by $20 \mathrm{ft} @ \$ 4$
B) $20 \mathrm{ft} @ \$ 8$ by $40 \mathrm{ft} @ \$ 4$
C) $14.1 \mathrm{ft} @ \$ 8$ by $56.6 \mathrm{ft} @ \$ 4$
D) $56.6 \mathrm{ft} @ \$ 8$ by $14.1 \mathrm{ft} @ \$ 4$