Task: Question Answering
Input (English): Problem: if the sales tax reduced from 3 1 / 2 % to 3 1 / 3 % , then what difference does it make to a person who purchases an article with market price of rs . 9000 ? 
Options: a ) 11 , b ) 13 , c ) 15 , d ) 18 , e ) 10
Output (English): c