i don't understand how to solve a following question.

Given the graph of the production possibilities frontier in the figure, which of the

following statements is TRUE?

A) The country has 2 units of labor, and it takes 0.5 unit of labor to produce 1 unit of

either good.

B) The country has 3 units of labor, and it takes 1 unit of labor to produce three drums

and 1 unit of labor to produce 3 1/3 pairs of shoes.

C) The country has 4 units of labor, and it takes 2 units of labor to produce eight drums

and 3 units of labor to produce three shoes.

D) The country has 5 units of labor, and it takes 1 unit of labor to produce 1.8 drums and

1 unit of labor to produce 2.5 shoes.