Find the Length and Width of a Rectangle That Has $12 \mathrm {~m} ; 12 \mathrm {~m}$

Multiple Choice

Find the length and width of a rectangle that has perimeter meters and a maximum area.

A) $12 \mathrm {~m} ; 12 \mathrm {~m}$ .
B) $16 \mathrm {~m} ; 9 \mathrm {~m}$ .
C) $1 \mathrm {~m} ; 23 \mathrm {~m}$ .
D) $13 \mathrm {~m} ; 11 \mathrm {~m}$ .
E) $6 \mathrm {~m} ; 18 \mathrm {~m}$ .