PLS HELP!!!! WILL MArK BRAINLIEST IF IT IS CORRECT!!!

What was one of the main reasons Europeans were able to conquer the Aztec
Empire?
A. They convinced Aztec slaves to rise up against the empire,
B. They got help from cities within the empire.
C. They convinced the Aztec people to change their religion.
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D. They were very popular with Aztec leaders,