Task: Question Answering
Input (English): Problem: a farming field can be ploughed by 6 tractors in 4 days . when 6 tractors work together , each of them ploughs 120 hectares a day . if two of the tractors were moved to another field , then the remaining 4 tractors could plough the same field in 5 days . how many hectares a day would one tractor plough then ? 
Options: a ) 144 , b ) 255 , c ) 148 , d ) 265 , e ) 320
Output (English): a