Answer:
XYZ Publishing Company is the owner of the cover design.
Step-by-step explanation:
When a business or even an individual hires someone to work for a specific job, the outcome of that job belongs to the employer.
For example, if I hire a carpenter and ask him to manufacture a specific type of chair that I like. Even f the carpenter contributed to the design of the chair, the chair and its design belong to me since I paid for it. Even if for some reason a lot of people like my chars and they ask the carpenter to manufacture more chairs, he would need my authorization to do it.