Task: Question Answering
Input (English): Problem: a , band c can do a piece of work in 11 days , 5 days and 55 days respectively , working alone . how soon can the work be done if a is assisted by band c on alternate days ? 
Options: a ) 5 days , b ) 8 days , c ) 9 days , d ) 10 days , e ) 11 days
Output (English): a