Arectangular prism is completely packed with 90 cubes of edge length 1/2 inch, without any gap or overlap. which of the following describes the volume of this rectangular prism? a: 11 unit cubes and 1 smaller cube of volume 1/8 cubic inch b: 22 unit cubes and 4 smaller cubes of volume 1/8 cubic inch each c: 11 unit cubes and 2 smaller cubes of volume 1/8 cubic inch each d: 22 unit cubes and two smaller cubes of volume 1/8 cubic inch each