Read this passage: By the early 1900s, European imperial powers had built up huge armies and navies to enforce their claims on colonies around the world. Each power raced to build a larger and more advanced army than its rivals in Europe. When Germany invested heavily in its navy, Great Britain and other European powers responded by pouring resources into their own naval forces. This led to a massive buildup of weaponry in Europe in the years before World War I.
Which contributing factor to World War I does the passage most clearly reflect?
A. The alliance system
B. Imperialism
C. Militarism
D. Nationalism​