In "The Unbreakable Code," why did John’s grandfather speak sternly when talking about the Navajo language?

A. He had forgotten Navajo when he was younger as well.

B. He was afraid John’s friends would keep him from speaking Navajo.

C. His grandfather had taught him Navajo

D. The Navajo language had helped his country win WWII.

PLS HELP I WILL MARK BRAINLIST IF CORRECT!! :)

Take a look at this online dictionary entry. language etymology middle english language, from old french language, from latin lingua ("tongue, speech, language”). noun 1. a form of communication using words either spoken or gestured with hands and structured with grammar, often with a writing system. 2. the ability to communicate using words. 3. nonverbal communication. 4. the vocabulary and usage in a particular field. 5. the words used in speech or a passage of text. 6. spoken or written words. which link would readers of this dictionary entry click if they wanted more information about the historical origins of the word "language”?