Solve the Problem $= 4 \mathrm {~km}$ , Width $= 2 \mathrm {~km}$

Multiple Choice

Solve the problem.
-The width of a rectangle is 6 kilometers less than twice its length. If its area is 56 square kilometers, find the dimensions of the rectangle.

A) length $= 4 \mathrm {~km}$ , width $= 2 \mathrm {~km}$
B) length $= 3 \mathrm {~km}$ , width $= \frac { 56 } { 3 } \mathrm {~km}$
C) length $= 7 \mathrm {~km}$ , width $= 8 \mathrm {~km}$
D) width $= 7 \mathrm {~km}$ , length $= 8 \mathrm {~km}$