Toward which city were Union forces heading
when they met the Confederates at
Fredericksburg?
A. Chancellorsville
B. Manassas
C. Richmond

The union forces where  heading  towards (C) Richmond when they met the Confederates at  Fredericksburg

Explanation:

The Battle of Fredericksburg refers to the battle that was fought between the Union forces and the Confederate Army of Northern Virginia in the year 1862.

The union forces where led by Maj Gen. Ambrose Burnside. and the Confederate Army of Northern Virginia General Robert E. Lee

Major General Ambrose Burnside led the Union toward Richmond and they headed towards  the Confederates at  Fredericksburg.

This battle (i.e. Battle of Fredericksburg)  was a big defeat  for the Union Army against the Confederate Army of Northern Virginia

Thus we can say that The union forces where  heading  towards (C) Richmond when they met the Confederates at  Fredericksburg