The correct answer is: C. Proprietary
The word "proprietary" means "relating to or characteristic of an owner or proprietor." It can also mean "belonging to or controlled by a particular person or company."
The word "propriety" means "the quality of being appropriate or fitting." It can also mean "the ownership of property."
The word "proprietor" means "the owner of a business or property."
The word "proprietorship" means "the state of being a proprietor."
