A metallic sheet is of rectangular shape with dimensions 48 m x 36 m. From each of its corners, a square is cut off so as to make an open box. If the length of the square is 8 m, the volume of the box (in m cube) is: Choose the correct choice.
A) 4120 m cube  B) 4140 m cube  C) 5140 m cube  D) 5120 m cube  E) none of these

Rationale: "explanation : l = ( 48 - 16 ) m = 32 m , [ because 8 + 8 = 16 ] b = ( 36 - 16 ) m = 20 m , h = 8 m . volume of the box = ( 32 x 20 x 8 ) m cube = 5120 m cube . option d"
Answer: D