C. is the answer because it indicate or referring to something by word, symbols
<span>D) Michelle's paintings stood out vividly when they were displayed against a neutral background.
The subordinate clause is "when they were displayed against a neutral background. Even though part of this clause could stand alone: they were displayed against a neutral background, using the word 'when' makes the clause dependent. We need to know what happened WHEN they were displayed. The rest of the sentence solves this - Michelle's paintings stood out vividly. </span>
The type of word needed is an action noun (not an act) one can perform on their own, as it is given the quantity of "a long" and you do not use adjectives to describe verbs. it would be D. Rant, as quibble. though it is a noun, you do not quibble alone, nor do you go on a quibble. You go on a rant. The other two are B. an adjective and C. a verb. D is the only word that truely fits the context.
