Imperialism is the cause of war best illustrated on the map. Option B is correct.
Imperialism is a policy or ideology by which a nation's rule is extended over foreign nations, often by military force or by gaining political and economic control of other areas.
The term imperialism may be applied to the colonization of the Americas between the 15th and 19th centuries, in opposition to New Imperialism, which refers to the expansion of Western Powers and Japan during the late 19th and early 20th centuries.