Task: Question Answering
Input (English): Problem: in a certain village , 20 litres of water are required per household per month . at this rate , if there are 10 households in the village , how long ( in months ) will 2000 litres of water last ? 
Options: a ) 5 , b ) 2 , c ) 10 , d ) 1 , e ) 12
Output (English): c