How did the traditional way of making firearms change in the late 19th century? A. Mass-production methods replaced it. B. Gunsmiths learned how to make rifles faster and better. C. Blacksmiths made guns instead of gunsmiths. D. It did not change at all.

A
Explanation: During the 19th century, industrialization began in Europe. Mass warfare became more common, and so it was important for guns to be easily reproduceable, replaceable, and compatible with other parts from other guns. Combining those two factors, mass standardized production of firearms was invented in order to facilitate for European large-scale warfare.