All of the following are true of Cortés's invasion of Mexico, EXCEPT that: a. smallpox proved to be a very powerful weapon against the natives.
b. Tenochtitlán held out for three months against a Spanish siege.
c. Cortés explained that the Spanish had a disease that only gold could cure.
d. regional Indian tribes attempted to help the Mexica against the Spanish.
e. more than 100,000 warriors were killed.