A and C are grammatically correct.
Translation of A: We see a snake.
Translation of C: We see Sergio.
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B and D are missing a small word.
Correction of B: Nosotros vemos *A* Tomas.
Correction of D: Nosotros vemos *A* Jorge.
They are both missing the word "a."
Answer:
No, nosotros no lavamos el carro
Felipe, no trabaja
Explanation:
The best word to fill in the blank would be cubanos.
Cubana- a female cuban
Cubano- a male cuban
Cubanas- more than one female cubans
We are left with Cubanos which means more than one male cubans.
I really hope this helps.