A rectangular pyramid with a base of 9 units by 4 units and a height of 7 units.
Which is the correct calculation for the volume of the pyramid?

A-One-third(36)(7)= 84 units3
B-One-half(36)(7) = 126 units3
C-36(7) = 252 units3
D-36(7)(3) = 756 units3