I would say the best answer for this question could be the Classical Period.
D is the correct answer.
In the badly drawn diagram attached, you will find the <em>yellow</em> represents wavelength, which is the distance between identical points on consecutive waves.
The <em>green</em> represents the amplitude, which is the distance between the origin (middle) and crest/trough (top/bottom)
If there were no copyright laws, you would not be able to protect your music after releasing it. People could take parts, or even your entire song and claim it as their own, and you would have no legal bounds or actions against the plagiarism of your work.
The curved line is a slur connecting the notes