What is the volume of the figure below if a = 9 units and b = 7 units?

A triangular prism placed above a cube. Cube has side a. triangular prism has base a ,height b, length of prism a.
Note: Figure is not drawn to scale.
A.
1,012.5 cubic units
B.
364.5 cubic units
C.
1,296 cubic units
D.
760.5 cubic units