what is the definition of opportunity cost?

a. please ignore this question, it was so this website will understand my question. My real question is below wit the number 1.

1.

Match each of the following to the diagram below (choose one or more):

a.Inefficient production of meat and fish

b.Productive efficiency

c.Technological advances in the production of meat and fish

d.The law of increasing opportunity cost

e.An unattainable combination of meat and fish

as in the image below i attach the graphs and the letters above the graphs and i need to match those letters to these answers written above.