Final answer:
To sue for copyright infringement, Richard must prove that his work was original, and that there was actual copying or potential access to the work by the infringer, as well as a substantial similarity between the two works.
Step-by-step explanation:
If Richard wishes to sue for copyright infringement, the most accurate statement that he must prove is that his work was original, and the infringer actually copied his work or that the infringer had access to his song and that the two works are substantially the same. This means that Richard does not only have to show similarity but also that there was copying or a reasonable opportunity for copying to have occurred. Additionally, he must demonstrate the originality of his song.
In copyright law, the mere fact that two works are similar is not enough to prove infringement. Similarly, incurring money damages or registering the song for copyright, though often part of the process, are not in themselves sufficient conditions to establish copyright infringement.
Examples like the case of Marvin Gaye's family winning a lawsuit over copyright infringement, where Pharrell Williams and Robin Thicke were found to have plagiarized Marvin Gaye's song, illustrate the importance of establishing that actual copying occurred or that the infringer had access, and that the two works are substantially the same.