Which word in the sentence does the adverb modify? The young child tightly gripped the green blanket. A. green B. blanket C. gripped D. young

That would be gripped because an adverb is a verb that's describing an adjective. The child gripped the green blanket. green is the adj and gripped is the verb

An adverb is a modifier that modifies a verb and often ends in -ly. "Tightly" is the adverb which modifies the verb C) "gripped."