Adverbs are those invariable words that modify the verb, which can be many types:
Adverbs of place.
Adverbs of time.
Adverbs of manner.
Adverbs of quantity.
Adverbs of denial.
Interrogative adverbs.
There are some guidelines that you can apply to identify adverbs of manner so, since many of them have the ending <em>"mente"</em> as is the case of <u><em>"claramente,"</em></u> on the other hand <u><em>"mucho"</em></u> is an adverb of quantity and <u><em>"allí"</em></u> is an adverb of place. The word <u><em>"estudia"</em></u> is discarded from the answer since being an action, it is classified as a verb.