Sharon's Company Has Written a New Computer Program, and She

Multiple Choice

Sharon's company has written a new computer program, and she has been asked to find a way to prevent people from copying the software they purchase and giving it to others who have not purchased the software.  
What can Sharon's company do to make sure a customer who purchases the program does not give it to someone else?

A) Acquire a copyright.
B) Obtain an EULA.
C) Use DRM.
D) Issue a license.