Read the sentence.
laughing at my question, he shook his head and said no.
which best identifies the word that is modified by the underlined participial phrase?
"laughing at my question" is underlined
1. he
2. head
3. question
4. shook

Hmm, I don't really understand the question and given I just started Language Arts in my classes I'm not familiar with this yet but I'll try and help. I looked up Participial Phrase and it said something about verbs. 4 is a verb so maybe it's 4? 1 is a pronoun, 2 and 3 are nouns and 4 is verb. "Participle Phrase is a form of a verb used in a sentence to modify a noun. " ... I'm thinking now it's 3 because it's a noun and it's in the participial phrase. I don't know. I don't think I helped much but I really don't get this. Sorry! 

This would be third person because they are using the correct pronouns that belongs to third person like he, the name, etc