because conocer is used more when you personally know someone/thing
saber is used when you know facts about someone or something.
se is conjugated in the yo form
sabes is conjugated in the tu form so this one is correct because you are asking someone if they know where the party is.
Answer:
pablo cena en la cafeteria?
Explanation:
¿Cómo se llama usted?
when I was in Spanish class we had to make it proper when first meeting an elder, so we used "usted."