The correct answer is to translate.
Does Francisco know who Gilberto is?
No, he doesn’t know him
No, Francisco doesn’t know who Gilberto is
Yes, he knows who he is
1. Si, yo tengo crema solar.
2. Si, yo compre los anteojos de sol.
3. No, yo no rente el barquito.
4. No, yo no rente los esquís acuáticos.
5. Si, yo use la computadora.
6. Si, yo busque información en el internet.
7. Si, yo envíe el correo electrónico anoche.
It would tienes because it goes with tú. I'm not sure how to really explain it but that's the ser you would use with tú. I hope this helps!