Task: Question Answering
Input (English): Problem: a box measuring 27 inches long by 15 inches wide by 6 inches deep is to be filled entirely with identical cubes . no space is to be left unfilled . what is the smallest number of cubes that can accomplish this objective ? 
Options: ['a ) 90', 'b ) 180', 'c ) 210', 'd ) 240', 'e ) 864']
Output (English): a