1. Circle c is the copyright mark.

2. Copyright mark is also called "copyright symbol". An American nickname for the copyright page. As a condition of protection, any person claiming copyright for a published work must bear a formal notice on all volumes.

3. According to U.S. copyright law, in order for a published work to be protected, a mark including the word copyright or its abbreviation or symbol must be included in an appropriate location in all volumes of the work. ;Year of first publication;Name of actual copyright holder. The requirement for such a mark as a condition of copyright protection for a published work is accepted by the Universal Copyright Convention, the Rome Convention and the Phonogram Convention, but under the Universal Copyright Convention the first item of the mark should always be the copyright symbol.

This means that the copyright has been registered. The R in the circle means trademark registration. Please note that many websites have this circle with a C mark at the bottom. This indicates that they have registered the copyright of their page. Please do not imitate or plagiarize.