Task: Question Answering
Input (English): Problem: if the simple interest on $ 2000 increase by $ 40 , when the time increase by 4 years . find the rate percent per annum . 
Options: a ) 1.2 % , b ) 0.5 % , c ) 0.7 % , d ) 0.9 % , e ) 0.3 %
Output (English): b