Task: Question Answering
Input (English): Problem: the c . p of 15 books is equal to the s . p of 20 books . find his gain % or loss % ? 
Options: a ) 25 % loss , b ) 16 2 / 8 % loss , c ) 16 3 / 3 % loss , d ) 36 2 / 3 % loss , e ) 56 2 / 3 % loss
Output (English): a