A) expressions, if they have no tone or expression in their voice/speech people tend to tune out and get bored. Example may include using different voices or tones for characters or emphasizing words that are hyperbole or an onomatopoeia.
B) keeps the audience/listener engaged by getting straight to the point, no getting distracted or taking a long time to get to the point you are trying to get across too.
C) if it’s a group of individuals or children you want to be personal and connect with them, this will cause them to feel more comfortable and welcoming while you are reading the book. They can relate to the story or what you’re trying to get across, since they can personally connect this way they think that you understand what you are trying to relate too.
Hope this helps