Answer:
General Clinton used a mask to write a secret message
Step-by-step explanation:
An explicit information is an information that is stated directly and clearly. An explicit information can be understood directly by reading the text. There is no ambiguity.
In this excerpt, it was stated directly that General Clinton used a mask to write a secret letter to General Burgoyne. There is no ambiguity in this statement, and it contains an explicit information from the text.