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