Answer: Option B: viste, vi.
Explanation: The dialogue is:
"—¿Qué _____ tú en la ciudad?
—_____ muchos monumentos, museos y parques"
The translation would be:
"-What did you___ in the city?
- I ___ a lot of monuments, museums, and parks."
The first sentence can be completed with "see", and the second one with "saw"
The right answer is the option B: where "viste" means things that the other persons saw in the travel to the city, so "viste" is used in "preterito perfecto" for "tu" or "you" (tu viste), and "Vi" is the preterito perfecto for "yo" or "I" (Yo vi)
So the complete dialogue would be:
"—¿Qué viste tú en la ciudad?
— Vi muchos monumentos, museos y parques."
