Final answer:
The correct answer is option A) 1521.
Step-by-step explanation:
The unification of the Aztecs and their subsequent driving out of the Spaniards from Tenochtitlan did not occur. Rather, after a series of engagements and political maneuvers, the Spanish, led by Hernán Cortés, and their native allies laid siege to the city and conquered the Aztec capital. Tenochtitlan fell on August 13, 1521, following a brutal siege that brought about the end of the Aztec Empire.
The Spanish arrival led to the spread of diseases like smallpox among the indigenous population, who lacked immunity. Coupling this with the strategic alliances formed by Cortés with other indigenous peoples like the Tlaxcalans, enemies of the Aztecs, they were able to weaken the Aztec resistance significantly. On a particularly tragic night for the Spaniards, known as La Noche Triste, in 1520, the Aztecs managed to temporarily drive away the Spaniards, resulting in many sacrifices of the captured at the pyramid of Huitzilopochtli.
Despite this temporary victory, Cortés returned and, after months of fighting and overcoming the resistance through a combination of warfare, disease, and political alliances, successfully conquered Tenochtitlan, marking a decisive moment in the colonization of the Americas by European powers.