Here's the situation: FED rules
When Libero serves they do not have to "sit out" when going back to serve. When she finally gets across the back row and makes the next exchange how long does she legally have to sit out?
A. One serve, no matter who wins the point - she can come in after one serve.
B. One 1/2 rotation - she can only return after the server from her team loses the serve.
C. One full rotation - she can only return after her team rotates again.
I know this is a basic question, but we had a big disagreement with a coach tonight.

I would love to have the rule number too if possible.