I long to see you recover speedily.
The word 'long' in the above sentence acts as a (an) ________.
A verb is used to express an occurrence, action , or state. It is the grammatical centre of the predicate in a sentence. Option C) verb is correct as long is a verb (it indicates an action). The other options are wrong as long is not used as a noun, an adjective or an adverb in the given sentence. The correct answer is C)verb.