Task: Question Answering
Input (English): Problem: p works 25 % more efficiently than q and q works 50 % more efficiently than r . to complete a certain project , p alone takes 50 days less than q alone . if , in this project p alone works for 60 days and then q alone works for 150 days , in how many days can r alone complete the remaining work ? 
Options: a ) 50 days , b ) 75 days , c ) 120 days , d ) 150 days , e ) 80 days
Output (English): c