In Science, There Is a System of Peer-Review, Where Nothing

In science, there is a system of peer-review, where nothing gets published until several other scientists have looked over the work. What is the purpose of this?

A) To give scientists something to do in their spare time.
B) To ensure that everything gets published.
C) To ensure that everything that gets published is as accurate and repeatable as is possible.
D) To ensure no one scientist has too much power.
E) To ensure that everyone agrees on the ideas of science.