Question

the \powder keg\ in the balkans refers to the
invasion of the region by outside forces.
political instability of the region.
efforts taken to ease tensions throughout the region.
large number of munitions factories built in the region.

Explanation:

The term "Powder Keg" for the Balkans was due to its complex ethnic - national makeup, overlapping claims, and rivalries among great powers, leading to high - levels of political instability and the potential for conflict to explode, much like a powder keg.

Answer:

B. political instability of the region