Answer:
A
Step-by-step explanation:
The volume (V) of a pyramid is
V = [tex]\frac{1}{3}[/tex] area of base × perpendicular height (h)
area of square base = 4² = 16 and h = 4, hence
V = [tex]\frac{1}{3}[/tex] × 16 × 4 = [tex]\frac{64}{3}[/tex] = 21 [tex]\frac{1}{3}[/tex] ft³
