Final answer:
The correct answer is option A) The Union forces.
Step-by-step explanation:
The question refers to the skirmishes in Baltimore, which is likely an indirect reference to the broader context of the Civil War rather than a specific set of skirmishes known by that name. The Union and the Confederacy faced substantial casualties throughout the Civil War, with different battles and skirmishes yielding different results. In the context of the entire Civil War, the Union suffered more overall casualties, but they also had a larger army and more resources.
The Confederate forces generally faced fewer casualties in any given engagement due to their defensive strategy and shorter supply lines, and often held tactical advantages when fighting on their own soil. Without the specifics of certain skirmishes in Baltimore and presuming the question refers to the general trend, historical evidence does not point definitively to either the Union or the Confederate forces as having more casualties in Baltimore.