The answer to this is symbol because symbol stands for an abstract idea such as an idea, quality, concept or condition.
Answer:
teach readers about a code system used during the American Revolution.
Explanation:
The lines "He substituted digits for words that would be used in messages. "Long Island," for example, was 728, "arms" was 7, and "city" was 88. There was a number for each month, such as 341 for "January." indicate that the author wants to teach the reader about a code system used during the American Revolution.
Also, the rest of the options don't make any sense whatsoever.
Hope this helps, and please mark me brainliest if it does!
Remember the sacrifices of the people who fought at Gettysburg.
