D.Ethos, or an appeal to ethics
Ethos appeals to one's character.
Answer:
Explanation:
The rain fell heavily when the clouds thickened and darkened.
That's an example of one.
The independent clause is The rain fell heavily. Those 4 words will stand by themselves as a complete thought. The dependent clause is when the clouds thickened and darkened.
The dependent clause tells you when it rains heavily. It will not stand on its own.
I'm pretty confident your answer is adjective. Hope this helped!