Sofia is married to Miguel, who is the brother of Jorge. As Isabel is Jorge's daughter, this makes Sofia her aunt by marriage. Therefore, Sofia is Isabel's aunt.

Carlos is the son of Jorge, and Luis is the son of Miguel. Because Jorge and Miguel are brothers, their children are first cousins to each other. This means that Carlos and Luis are first cousins.
Jorge has two children, a son named Carlos and a daughter named Isabel. Jorge's brother, Miguel, is married to Sofia, and they have two sons, named Luis and Marco. How are Sofia and Isabel related? Also, what is the relationship between Carlos and Luis?

Provide a very short response.