Which of the following will cause the marginal cost curve to shift Upward?

I.The firm hires more workers.

II.Technological innovation results in an improvement in labour productivity.

III. The price of the fixed input increases, thereby increasing fixed costs.

1) I, II and III

2) I and III only

3) III only

4) I only

5) None will cause the marginal cost curve to shift up

Which # is the correct Multiple choice and why?