Task: Question Answering
Input (English): Problem: the simple interest on a certain sum of money at the rate of 5 % p . a . for 8 years is rs . 840 . at what rate of interest the same amount of interest can be received on the same sum after 5 years ? 
Options: a ) 6 % , b ) 8 % , c ) 9 % , d ) 10 % , e ) none
Output (English): b