The correct answer is A. the Spanish had muskets and cannons and the Aztec did not.
The Spanish conquest of the Aztec Empire in the early 16th century was significantly aided by their advanced weaponry, including firearms such as muskets and artillery pieces like cannons, which the Aztecs did not possess. While the Aztec warriors were skilled and had their own weapons, including wooden swords with obsidian blades and various types of projectile weapons, they were not equipped with the gunpowder-based technology that the Spanish had.