Triple

Target entity: Battle of Ball's Bluff
Context triple: [Ball's Bluff National Cemetery, commemorates, Battle of Ball's Bluff]

• A. Battle of Ball's Bluff chosen
  The Battle of Ball's Bluff was an early and disastrous Union defeat in the American Civil War, fought in October 1861 along the Potomac River in Virginia, which led to political upheaval in Washington and the creation of the Joint Committee on the Conduct of the War.
• B. Battle of Fort Stevens
  The Battle of Fort Stevens was a July 1864 American Civil War engagement in which Union forces repelled Confederate troops attacking the defenses of Washington, D.C., marking the only time a sitting U.S. president, Abraham Lincoln, came under direct enemy fire.
• C. Battle of Monocacy
  The Battle of Monocacy was an 1864 American Civil War engagement in Maryland in which Union forces delayed a Confederate advance toward Washington, D.C., earning it the nickname "The Battle That Saved Washington."
• D. Battle of Cedar Mountain
  The Battle of Cedar Mountain was an American Civil War engagement in August 1862 in Virginia, where Confederate forces under Stonewall Jackson clashed with Union troops as part of the Northern Virginia Campaign.
• E. Battle of Antietam
  The Battle of Antietam was a pivotal 1862 clash in the American Civil War, known as the bloodiest single day in U.S. military history and a turning point that enabled Abraham Lincoln to issue the Emancipation Proclamation.
• F. None of above.
• G. Unsure - the case is ambiguous/there is not enough information to decide.