In this exercise you have to complete the blank with the correct option. In this case the correct option would be "selva tropical". We know that by context. The sentence in English says something more or less like this:
-The......................... of Peru is very hot, especially in summer.
So the missing word can't be "church", "Museum", or "Cathedral".
So the correct option would be:
La selva tropical del Perú es muy calurosa, sobre todo en verano.
