How to say Who in French?

What does Qu mean in English? French translations and examples in context.

Who is translated in French by...

Qui?
Who?

Qui es-tu?
Who are you?

Qui a fait ça?
Who did this?

C'est de la part de qui?
Who's calling?

Qui gagnera la course?
Who will win the race?

Ça va bien... Qui est à l'appareil?
I'm good... Who's speaking?

Ah oui? Pour qui travaillez-vous?
Really? Who do you work for?

Ceux qui volent sont punis.
The ones who steal are punished.

C'est nous qui sommes désolés, madame.
We are the ones who are sorry, ma'am.

Who? Adverbs in French.