Given the production possibilities frontier below:

a$.(2$ pts$)$ Where is the opportunity cost of capital goods production the lowest, at point $"1"$ or point $"2"?$ How do you know?

b$.(1$ pt$)$ How might Country A actually be able to produce the combination of goods represented by point $"4"?$ Please give me an example of a change that would enable this.

c$.(1$ pt$)$ A tricky one$--$if Country A was producing the combination of goods represented by point $"3",$ what would be the opportunity cost of an additional unit of capital goods?