The first statement is the most accurate:
"The global depression caused Japan to invade Manchuria to acquire necessary resources and improve its economy."
This statement correctly identifies Japan's invasion of Manchuria in 1931 as a response to the economic pressures of the Great Depression, emphasizing the desire for resources and economic improvement. The other statements incorrectly assign actions to Japan that were not historically accurate, such as invading Czechoslovakia, Ethiopia, or Austria, which were not actions taken by Japan during that period.