Task: Question Answering
Input (English): Problem: if x - y - z = 03 x + 4 y + 3 z = 45 x + 2 y + 7 z = 22 , what is the value of z ? 
Options: a ) 3 , b ) 4 , c ) 5 , d ) 2 , e ) 1
Output (English): a