Task: Question Answering
Input (English): Problem: in a certain supermarket , a triangular display of cans is arranged in 9 rows , numbered 1 through 9 from top to bottom . each successively numbered row contains 3 more cans than the row immediately above it . if there are fewer than 120 cans in the entire display , how many cans are in the seventh row ? 
Options: a ) 13 , b ) 15 , c ) 17 , d ) 19 , e ) 21
Output (English): d