Read the excerpt from “Tools of the Spymaster." The numbers that Major Tallmadge assigned to members of the Culper Ring were fro
m a secret writing system he invented. 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." He made four copies of his codes. He kept one and gave the others to Woodhull, Townsend, and General Washington. For words that did not have a number code, Tallmadge gave his agents a cipher. In a cipher, each letter in a message is replaced by another letter or a number. Which statement best expresses the central idea of the excerpt? Major Tallmadge developed a unique code system so that the Americans could send secret messages. Major Tallmadge did not trust anyone with his codes other than Woodhull, Townsend, and General Washington. The number codes used in secret messages were assigned only to members of the Culper Ring. The code system Major Tallmadge designed did not work because some words did not have a number code.
The correct answer is A. Major Tallmadge developed a unique code system so that the Americans could send secret messages.
Explanation:
To find the central idea in a text, ask yourself what is the main idea the author expresses?. For example, in the passage presented the author focuses on the system Major Tallmadge created and how this system was very elaborated or complex, which is shown through details such as "He substituted digits for words" or "Tallmadge gave his agents a cipher". Moreover, the author implicitly suggests this was used for Americans to send secret messages as he mentions important American military leaders such as "Woodhull, Townsend, and General Washington" and shows how important was that the messages were only understood by few. In this context, the main idea is "Major Tallmadge developed a unique code system so that the Americans could send secret messages".
