Final answer:
The correct answer is option A) Advanced weaponry.
Step-by-step explanation:
The Spanish conquest of the Aztecs was facilitated by multiple factors, including advanced weaponry, diplomacy, the spread of disease, and the acquisition of local allies. The Spanish, led by Hernán Cortés, possessed steel armor and swords, and had the tactical advantage of cavalry. Diplomatic engagements helped them to form alliances with local tribes disenfranchised by Aztec rule, such as the Tlaxcalans and the Totonacs, who saw the Spanish as liberators and contributed significantly to their military efforts.
Moreover, diseases like smallpox, to which the Aztecs had no immunity, devastated the indigenous population and weakened Aztec resistance significantly. Thus, recruiting native allies played a crucial role in the Spanish conquest, as did the other aforementioned factors.