A 4*5 ft = 20 foot - no good
B circumference of circle = 2* pi *3 = 6 pi = 18.85 ft so this will use a lot of the 19 ft.
C. right triangle triangle - perimeter = 6 + 6 + 6*sqrt2 = 20.49 - no good
D. rectangle perimeter = 16 + 8 = 24
Answer is choice B