Answer:
The correct answer is the South, because in the initial battles and skirmishes Southern Army managed to defeat the Union Army. Among those battles the most famous ones were the battles of Battle of Bull Run and Battle of Wilson's Creek in Missouri. The main reason for this is that the Southern Army had larger number of capable generals who managed to tactically defeat their opponents.
Step-by-step explanation:
Union Army although had larger numbers didn't had such a strong leadership on the battlefield in the beginning. That is why in most of the first battles during the first year of the war they were defeated.