Read the excerpt from “Tools of the Spymaster." General Clinton, concerned about what General Howe was planning and doing, made use of a mask to write a secret message in a letter to General Burgoyne.

Before writing the letter, Clinton had placed an hourglass-shaped mask on a piece of paper and then had formed the secret message within that shape.

The unmasked letter had enough false information in it to fool any American who happened to see it. But when Burgoyne viewed the letter with the mask, he read Clinton's view of the real situation: Howe has made a bad move; I don't have enough men to do anything about it
Which statement is best supported by text evidence from the excerpt?
A. General Howe was embarrassed by his mistake.
B. General Clinton hoped that General Burgoyne could help him.
C. The Americans read General Clinton’s letter to General Burgoyne.
D. The Americans did not have the mask to read General Clinton’s letter.