A copyright gives to owner the exclusive right to use an original work. "Use" is defined to include present, perform, produce copies of, and sell the right to use to others.
The small "c" in a circle on a work, usually next to a date, denotes a copyright on that work. The mark is optional, but can be helpful in a legal case where a person is trying to prove he or she copyrighted the work.
The job description of a copyright attorney is to advise clients registering a trademark, and the laws regarding the fair use or infringement of a copyright.
Contact a copyright lawyer in United States for legal advice on disputes involving copyrights or copyright infringement.