Final answer:
4) The State Legislatures
Montezuma treating the Spanish as honored guests, which led to him being taken hostage, gave the Spanish a significant advantage, ultimately aiding their conquest of the Aztec Empire.
Step-by-step explanation:
According to Source 4, the action by Montezuma that gave the Spanish an advantage in defeating the Aztec was Montezuma treating the Spanish like honored guests.
Montezuma II, the Aztec emperor, initially welcomed Hernán Cortés and his men, allowing them into the heart of the Aztec Empire, Tenochtitlán.
This grave miscalculation provided Cortés the opportunity to take Montezuma hostage, thereby destabilizing the Aztec leadership and making it easier for the Spanish forces to establish control and ultimately lead a rebellion against the Aztecs.