Respuesta :
The correct answers would be questions D " Did any of the Japanese or German students learn to speak Navajo" and E " What kind of code did the American Indians use during World War I". These are the questions that could help the reader understand the military leader's fear, since if the answers are yes they did learn to speak it, and a simple code, (respectively) then it would be perfectly sane to feel apprehension at using the same code again. Options A, B and C are not relevant because they do not contribute to the subject, for example, it doesn't matter how many people spoke Navajo before World War I, what is important is how many can learn it.
The questions which would improve the reader’s ability to understand the military leaders’ fear that the code would no longer be effective are:
- " Did any of the Japanese or German students learn to speak Navajo"
- " What kind of code did the American Indians use during World War I"
What is a Code?
This refers to the use of encryption to pass across information or communication in order to prevent eavesdropping by the enemy so they would not be able to listen.
With this in mind and from the given text, we can see that the military leader was afraid that there use of code was no longer effective because he thought that the enemies could speak Navajo.
Read more about use of codes here:
https://brainly.com/question/13655692