Final answer:
Within a single generation of Columbus's death, the group of Spanish conquistadores that failed to expand beyond the Caribbean is the one that conquered and claimed Central America.
Step-by-step explanation:
Within a single generation of Columbus's death, the group of Spanish conquistadores that failed to expand beyond the Caribbean is option 3) Conquered and claimed Central America. While other conquistadores explored and conquered various parts of the Americas, this group mainly focused on Central America and did not venture further north or south. It's important to note that the Spanish had extensive exploration and conquest efforts across the Americas, but this specific group did not expand beyond Central America.