What is one of the key characteristics of works protected by copyright?

One of the key characteristics of works protected by copyright is that they must be original and fixed in a tangible form. This means that the work must be the product of the author's creativity and not a mere copy of someone else's work. Originality does not require that the work be unique or novel in a universal sense; rather, it must demonstrate some level of creativity. Additionally, the requirement to be fixed in a tangible form means that the work must be expressed in a medium that is permanent enough to be perceived, reproduced, or otherwise communicated. This includes a wide range of formats, such as written documents, paintings, films, and digital media.

The other choices do not accurately reflect the fundamental requirements for copyright protection. For instance, while publication can affect certain rights under copyright law, it is not a prerequisite for protection. Similarly, copyright applies to both digital and non-digital works, and it is distinct from trademark law, which is unrelated to the original fixation of a creative work. So, the emphasis on originality and fixation in tangible form is what truly defines copyrightable works.