Task: Question Answering
Input (English): Problem: pat , kate , and mark charged a total of 135 hours to a certain project . if pat charged twice as much time to the project as kate and 1 / 3 as much time as mark , how many more hours did mark charge to the project than kate ? 
Options: a ) 18 , b ) 36 , c ) 75 , d ) 90 , e ) 108
Output (English): c