Detailed Instructions: In this task, you need to answer the given multiple-choice question on geometry. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.
Q: Problem: how many 4 x 5 x 8 cubes could fit in a 10 x 16 x 84 box ? 
Options: a ) 84 , b ) 90 , c ) 85 , d ) 77 , e ) 64
A:
a