Angie packed same-size cubes into a rectangular prism.

Image shows a base of cubes 3 units long, 2 units wide, and with a column of cubes 1 cube wide and 7 cubes tall.

What is the number of cubes needed to fill this prism?

A.
20 cubes

B.
35 cubes

C.
36 cubes

D.
42 cubes

The base of the prism has an area of $3\cdot 2=6$ square units. The column has a height of 7, so it contains 7 cubes. Therefore, the total number of cubes needed is $6\cdot 7=\boxed{\textbf{(C)}\ 36}$.

The answer is C