Task: Question Answering
Input (English): Problem: in a certain brick wall , each row of bricks above the bottom row contains one less brick than the row just below it . if there are 5 rows in all and a total of 100 bricks in the wall , how many bricks does the bottom row contain ? 
Options: a ) 18 , b ) 16 , c ) 17 , d ) 15 , e ) 19
Output (English): a