Answer to Question 1
C Answer C uses the definition of scarcity on page 2.
Answer to Question 2
Yes. A perfectly competitive firm should keep investing in capital up to the point where the expected rate of return is equal to the interest rate. In this case, the expected rate of return on the investment is higher than the market rate of interest. This implies that the opportunity cost of the funds used to purchase the structure is lower than the expected revenues from the structure. Thus, it was a good decision.