Answer:
A. They exchanged coded messages the Japanese could not understand which gave the united states an advantage, is the correct answer.
Explanation:
420 Navajo men worked in the pacific theatre during the second world war to work as code talkers. Navajo is an unwritten and complex language and acted as effective tool for transmitting vital information in the field. During the second world war many Navajo people were recruited by the marines. They contributed by serving as code talkers and helped US to make decisive moves in the pacific. Their contribution came into light when the program was declassified in 1968.Today less than 11 code talkers survive.