Answer:
The correct answer is B. The event that led to the decline in McClellan's popularity was that Confederate soldiers almost invaded the White House after the Battle of Antietam.
Explanation:
After the defeat of Union troops under General Irvin McDowell in the First Battle of the Bull Run, George McClellan received command of the Potomac Army in the summer of 1861, which had to bear the brunt of the fighting. From November 5, 1861 to March 11, 1862, he was also commander in chief of the army. As army commander in chief, he proved to be an excellent organizer; but also as an overly hesitant military leader. He formed the demoralized force into a powerful army, but was then reluctant to deploy it. He tended to make grotesque misjudgments of the balance of power by repeatedly overestimating the strength of the opposing troops and demanding reinforcements. It was not until massive government pressure that he advanced in March 1862 against the Confederate capital in Richmond, Virginia. He won most of the battles against the outnumbered Confederate Northern Virginia Army General Robert E. Lee, but withdrew from Virginia unsuccessfully after the Seven Days Battles.
McClellan was called to Annapolis to organize a new army. On September 17, 1862, he fought against General Lee in the bloody Battle of Antietam, which proved to be a strategic win with Lee's retreat from Maryland, but failed to defeat the weakened opponent (whom he again considered much stronger than it was in truth) and possibly end the war early. This renewed hesitation cost him command of the Potomac army; Abraham Lincoln replaced him with Major General Ambrose E. Burnside.
