D. The area filled with smoke because there was a fire burning
The word "intervene" is a verb that means "to come between" and that is the reason why the letter "D" is the correct answer to this question.
It is a verb because verbs are words that represent an action and, on the other hand, adverbs are words that modify verbs, adjectives and other adverbs.
Looks like logos I’m pretty sure since logos is logic and facts