A descriptive quote is simply a quote that throughly describes and gives details about a subject or in this case a character.
Without more information on your assignment, my best understanding is that your teacher is looking for a quote from whatever literary piece you are reading that best describes each of the characters.
Introduced is a regular verb because all you did was add -ed at the end. Good luck!
C) We went to hear the man himself speak.
Himself is an intensive pronoun. Intensive and reflexive pronouns end use the object form of the pronoun and end in -self. Intensive pronouns are found immediately after the antecedent. In this case, after "man" because "himself" is intensifying "man".