3. Suppose that a college professor is creating an exam in her university office. Which of the followingwould be an example of a factor of production used by the professor? (i) the professor’s time  (ii) a computer software program into which the professor types the exam questions (iii) the physical space of the professors office where she works when creating the exam (iv) the interest on the professor’s home mortgage
(A) (i) only
(B) (i) and (ii) only
(C) (i), (ii), and (iii) only
(D) (i), (ii), (iii), and (iv)