They appeared to me denizens of a brilliant existence. (“The Bass, the River, and Sheila Mant")

A. actors
B. environmentalists
C. deserters
D. inhabitants

D. inhabitants

To determine the answer to this question, we need to understand the context of the sentence. It appears to be a quote from the story "The Bass, the River, and Sheila Mant."

In this sentence, the word "denizens" means inhabitants or residents. The speaker is describing the people or beings that they encountered as if they belonged to a "brilliant existence" or a glorious world.

Now, let's look at the options provided:
A. actors - This option does not fit the context of the sentence. There is no indication that the people the speaker encountered are actors.
B. environmentalists - This option also does not fit the context. There is no mention of the people being involved in environmental activism or any related activities.
C. deserters - This option does not seem to fit the context either. Deserters typically refer to individuals who abandon a duty or cause, and there is no indication of this in the sentence.
D. inhabitants - This option matches the meaning of "denizens" in the sentence. It refers to the people who live in a particular place.

Therefore, the correct answer is D. inhabitants.