Which questions do adverbs answer about the words they modify?
a. to what degree?
b. in what manner?
c. when? and where?
d. all of the above

The questions that adverbs answer about the words they modify are: To what degree?, In what manner?, and When? and Where?. Therefore, the answer is letter D. All of the above. Adverbs are words that are used to describe a verb, an adjective or an adverb too. 

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