Answer:
d.all of the above
Step-by-step explanation:
Hernán Cortés was a Spanish conquistador(conqueror) who conquered the Aztec empire in 1521 and claiming Mexico(the aztecs) for Spain.
Cortes came with 16 horses(of which the aztecs have not seen before and therefore scared of. they described as beasts with two heads and six legs), 14 cannons, steel swords and crossbows. This made them stronger in battle against the Aztecs.
One of Cortés' men contracted smallpox from a member of the force from Cuba. He died during the Aztec rebellion and when his body was looted, an Aztec caught the disease which spread like wildfire among them because the Aztec people had no immunity to it.
When Cortés' army regrouped and re-entered Tenochtitlán. They found that the city's society had crumpled as a result of the disease. More than 3 million Aztecs died from smallpox, this helped the Spaniards in conquering the Aztecs.