Answer:
Adverb
Explanation:
I think, but am not 100% sure, I am more like 75% sure. Super sorry if you get this wrong.
It should be noted that "smart" as used in the sentence is B. Adverb.
It should be noted that an adverb simply means a word that is used to modify a verb.
In this case, the sentence is "My sister is sister is very smart". Smart in this case is an adverb. It helps in modifying the verb.
Learn more about adverb on:
https://brainly.com/question/912194
