What type of work is protected under copyright?

The accurate choice highlights that copyright protection extends to works that are fixed in a tangible medium of expression. This means that for a creation to be eligible for copyright, it must be recorded in some form that can be perceived, reproduced, or otherwise communicated, such as a written document, audio recording, or a visual artwork.

For instance, a novel, a painting, or a song that has been recorded in a physical format all qualify for copyright protection. The key element here is the "tangible medium," which differentiates these protected works from ideas or concepts that have not been expressed in a measurable fashion, which are not covered by copyright law.

In contrast, the other options do not align with how copyright laws define protected works. For example, musical compositions alone do not encapsulate the full scope of copyright, as it encompasses various forms of creative expression. Word-of-mouth statements are transient and lack the permanence needed for copyright protection. Finally, public domain works are not protected by copyright, as they are either no longer under copyright protection or were never eligible to receive it.