Task: Question Answering
Input (English): Problem: in the coordinate plane , points ( x , 5 ) and ( 9 , y ) are on line k . if line k passes through the origin and has slope 5 / 9 , then x - y = 
Options: a ) 4 , b ) 6 , c ) 5 , d ) 8 , e ) 7
Output (English): a