Which conflict came first in World War II?

A. Britain and Germany

B. The Soviet Union and Poland

C. China and Japan

D. Germany and France

D.?

The answer is C) China and Japan.

The second Sino-Japanese War (as the historians call it), or China vs. Japan started in 1937. This was way earlier than the conflicts in Europe.

In the other hand, The Soviet Union vs. Poland was the second war of WWII. Germany and Soviet Union divided Poland between them before the invasion and each invaded separately.

Germany and France started fighting when Hitler finished with Poland and invaded France.

While invading France, Germans used Belgium as a milestone, and Britain was guaranteed Belgium's sovereignty, so Britain involved too.