Answer: The vocal quartet.
Quartet: A group of four people or things.
In this case, a group of four people playing music or singing together.
According to the Jo-Hari window model, blind spots C.) SOMETHING THAT THE SENDER DOESN'T KNOW BUT THE RECEIVER DOES.
Blind spots are facts known to others but not known to self.
Disney studios rules of animation are written in The Illusion of Life.
Hope this helps :).
