Question

¿Tú _________ que mañana tenemos las clases de teatro?
conoces
sabes
sabemos
conociste

Answer 1

Simple....

Tu sabes que mañana tenemos las clases de teatro?

Thus, your answer.

Answer 2

the answer would be "sabes" it means do you know, conoces also means do you know, but in the meaning of do you know someone, and sabes is do you know something, Sabemos means we know, and conociste means did you meet

Hope this helps