Amajor challenge of nationalism is a. militarism b. leadership c. unification d. competition !

A major challenge of nationalism is "D. Competition".

The correct answer is - A. militarism.

Nationalism can go either way, either to be peaceful and restrictive towards people from outside, or to go aggressive towards the minorities or other countries. Unfortunately, the second way seems to prevail and the nationalist countries are often becoming militaristic, which causes a major concern globally,and is a huge challenge for the people that idolize this type of political practice to not allow it to become a destructive force, instead of being a way of preserving the nation's culture, traditions, religion, way of life etc.