Task: Question Answering
Input (English): Problem: a hall is 15 meters long and 10 meters wide . if the sum of the areas of the floor and the ceiling is equal to the sum of the areas of four walls , what is the volume of the hall ( in cubic meters ) ? 
Options: a ) 600 , b ) 700 , c ) 800 , d ) 900 , e ) 1000
Output (English): d