Your parents want to buy house in another country so the family can spend the summer there. they like to look at a variety of choices, from tall buildings to small detached houses, two ranches. they prefer a vibrant big city. espaba guinea ecarorial argentina costa rica

Argentina.

Explanation:

They want to buy a house in another country so the family can spend the summer there and they are looking for tall buildings and small detached houses, two ranches, etc. So the best place in South America to find a place with those characteristics is Argentina. It couldn't be Spain because it belongs to another continent. Then, it couldn't be Costa Rica because it is in central America and it couldn't be Guinea Ecuatorial because it belongs to another country.

Argentina is a country located in South America and you can find tall buildings in Buenos Aires (the Capital City of the country). Then, you can find small detached houses in the provinces or even in Buenos Aires.