We use pronouns so that we are not repetitive.
Answer: A) or the first option.
A pronoun is really a word that takes the spot of a noun, without pronouns sentences really wouldn't make sense or be clear here are examples.
Deaththekid101 answered a question
He answered a question
The spider is crawling
It is crawling
Zaxby's is the best resturaunt
This is the best resturaunt
See? pronouns take places so its important we have them.