The correct answer is C. humanism
Here's a small list of popular books that can help and introduce you to Ancient India. They are all available in English, by the way.
1- "A History of India, vol. 1: From Origins to 1300" (Romila Thapar)
2- "Ancient India as Described in Classical Literature; Being a Collection of Greek and Latin Texts Relating to India, Extracted from Herodotus and Other" (John Watson McCrindle)
3- "The Philosophy of Ancient India" (Richard von Garbe)
4- "Ancient India: in Historical Outline" (D.N. Jha)
5- "The Ancient Geography Of India" (Alexander Cunningham)
The Navajo code, which was not really a new code, was used during WWII.
The Navajo code could not be deciphered because it wasn't a code at all it was the native language of the Navajo.
Answer:
Battle of Otumba
Before reaching Tlaxcala, the scanty Spanish forces arrived at the plain of Otumba Valley (Otompan), where they were met by a vast Aztec army intent on their destruction. The Aztecs intended to cut short the Spanish retreat from Tenochtitlan and annihilate them.