Ayer hubo varios problemas en la escuela.
Answer: The space should be filled with "grande".
Explanation: This statement can be translated to;
Carolina: The Prado Museum is one of the biggest in Spain.
Diego: Incredible! This means that it has many artworks and paintings.
3. Francisco & Paco are very well informed about modern art.
Hotel
Hope the answer helps! My first lenguage is Spanish so there might be a VERY small to no chance im wrong! :)