The most appropriate comparison between the situations leading up to the invasions of China and Poland is:
B. Japan and Germany invaded other countries before invading China and Poland.
Both Japan and Germany had expansionist policies that led them to invade neighboring territories before their respective invasions of China and Poland. Japan's militaristic expansion in Asia included invasions of Manchuria in 1931 and subsequent conflicts with China in the 1930s. Similarly, Germany had invaded Austria and Czechoslovakia leading up to the invasion of Poland in 1939.