Which markings are recognized as an official copyright notice?

The correct answer identifies the markings "C in a circle" and "P in a circle" as recognized official copyright notices. The "C in a circle" signifies copyright protection, indicating that the work is protected under copyright law. It is a widely recognized symbol denoted by ©, which is used to inform the public that the creator maintains ownership and rights over the original work, whether it be literature, music, art, or other forms of creative expression.

The "P in a circle," or ℗, represents the phonorecord copyright, which specifically pertains to recorded music and sound recordings. This marking informs consumers that rights are claimed over the recorded performance, distinct from the underlying musical composition itself.

While other symbols like the ™ symbol and the registered mark are indeed important in the realm of intellectual property, they do not specifically represent copyright in the same formal manner as the symbols for copyrights do. The reference to the abbreviation "Corp" is also unrelated to copyright and pertains instead to corporate designations. Thus, answer C appropriately identifies the symbols directly associated with copyright protection in line with established legal standards.