Answer:
e. outsourcing.
Step-by-step explanation:
Based on the information provided within the question it seems that what Zappos is doing is called outsourcing. This is the act of when a company hires a third party company to undertake all the responsibilities of a certain task or division of the contracting company. Which in this situation Zappos is outsourcing all of their distribution responsibilities and tasks to UPS who are most likely better equipped to handle this and in a cheaper manner.