The correct answer is C) he did not improvise or change.
What ultimately led to Burnside losing the Battle of Fredericksburg was that he did not improvise or change.
The Battle of Fredericksburg was held on December 13, 1863. The Army of the Potomac was commanded by Ambrose Burnside. He ordered his men to attack both flanks of General Robert E. Lee Confederate troops settled in Fredericksburg. The Southern troops contended the Union Army although they had fewer soldiers. In the end, the victory was for General Lee and his Confederate troops. What ultimately led to Burnside losing the Battle of Fredericksburg was that he did not improvise or change.