An increase in personal saving as a percentage of disposable income contributes to capital deepening

Short-run supply curves for perfectly competitive firms tend to be upward sloping because:

A) there is diminishing marginal product for one or more variable inputs. B) marginal costs increase as output increases. C) marginal fixed costs equal zero. D) A and B are correct. E) B and C are correct.

Which of the following would be considered an investment in human capital?

a. education b. a teacher's blackboard c. the purchase of a new computer to enhance labor productivity d. All of the above are correct.