Which private policing agency thwarted the alleged Baltimore Plot to assassinate president-elect Abraham Lincoln?

• A. The Bow Street Runners
• B. The U.S. Secret Service
• C. The Metropolitan Police
• D. The Pinkerton Agency

Answer: (D)

The key idea is recognizing who provided private security and intelligence in the United States around Lincoln’s inauguration. Allan Pinkerton’s agency was a private detective outfit that actively protected leaders and investigated threats in that era. They uncovered the Baltimore Plot to assassinate Abraham Lincoln during his journey to the inauguration, supplied critical warnings, and helped reroute Lincoln’s travel to avoid the attack. That’s why the Pinkerton Agency is the correct choice. The other options are either London-based organizations or a federal agency whose protective duties didn’t apply in this 1860s context.