C) when because it doesn't really talk about the time of occurrence
Overall, Therefore, Reflecting back On,
It'd help if you'd provide the sentence.
Ariel and Caliban are decidedly different in nature and appearance. Ariel as his name proposes is an ethereal and spirit. On the other hand, Caliban is uncultured and un human. The two are associated to the Witch Sycorax who governed the island before Prospero. Hope it helped.