-Robinson Crusoe Divides His Time Between Catching Fish and Gathering

-Robinson Crusoe divides his time between catching fish and gathering fruit.Part of his production possibilities frontier is given in the above table.If Mr.Crusoe is on his PPF and he increases the amount of fruit he gathers from 56 to 90 kilograms,the opportunity cost is

A) 90 kilograms of fruit.
B) 34 kilograms of fruit.
C) 37 kilograms of fish.
D) 17 kilograms of fish.
E) 31 kilograms of fish.