Final answer:
The subject pronoun that best replaces 'Los amigos' in the sentence is 'Ellos'.
Step-by-step explanation:
The subject pronoun that best replaces 'Los amigos' in the sentence is Ellos.
Ellos is the third-person plural subject pronoun, which is used to refer to a group of male and/or female friends. In this case, it represents that the friends are from Florida.
For example, the sentence 'Ellos son de Florida' means 'They are from Florida'.
Learn more about Subject pronouns in Spanish