What alarmed Richard Garrett about Booth?

• A. Booth's nervous reaction when questioned
• B. Booth's attempt to flee the premises
• C. Booth's claim of being a Union officer
• D. Booth's reaction to the riders passing the house

Answer: (D)

The main idea here is how external signs of pursuit reveal danger when someone is hiding. Richard Garrett was alarmed by Booth’s reaction to the riders passing the house because that moment showed the threat was real and close. Hearing or seeing riders nearby meant federal search parties could be scouring the area, and Booth’s tense, anxious response confirmed to Garrett that their concealment was in serious jeopardy. It wasn’t about Booth’s words or past behavior; it was the immediate cue of those riders and Booth’s instinctive fear in the moment that underscored the imminent risk of being discovered.