C. Navegar: it means to navigate and since you are at a lake it is the only one that makes sense since you wont be a: getting a key or b: bidding on something or d: exchanging money.
"A él" means to/for him. "A ella" means to/for her- él means "him" and ella "her".
A.1 El
A.2 Yo
A.3 Nosotras
A.4 Usted
A.5 Ustedes
A.6 Tú
A.7 Ellos
A.8 Ella
1B va
2B van
3B voy
4B vamos
6B va
7B van
8B va
1C voy
2C van
3C vamos
4C vas
5C va