Database Design - one-to-one relationships - design methodology

Describe the different ways of implementing one-to-one relationships. Assume you are maintaining information on offices (office numbers, buildings, and phone numbers) and faculty (numbers and names). No office house more than one faculty member; no faculty member is assigned more than one office. Illustrate the ways of implementing one-to-one relationships using offices and faculty. Which option would be best in each of the following situations?

a. A faculty member must have an office, and each office must be occupied by a faculty member.
b. A faculty member must have an office, but some offices are not currently occupied. You must maintain information about the unoccupied offices in an Office relation.
c. Some faculty members do not have an office, but all offices are occupied.
d. Some faculty members do not have an office, but some offices are not occupied.