Which of the following statements correctly describes the relationship between volume (v) and number of moles (n) illustrated in the following plot for a gas constant temperature and pressure.

I think the correct answer from the choices listed above would be the last option. The relationship between volume (V) and number of moles (n) illustrated in the following plot for a gas constant temperature and pressure would be a direct proportional. As what we can see in the graph, as the volume increases the number of moles increases as well. Hope this answers the question.