Question

Which event in 1935-1936 proved that the League of Nations could not protect small nations from attack by larger ones? A. Hitler’s attack on Poland B. Hitler’s takeover of Czechoslovakia C. Mussolini’s conquest of Ethiopia D. the Soviet Union’s invasion of Finland

Answer 1

That's likely (C) Mussolini's conquest of Ethiopia. The League of Nations basically twiddled their thumbs over the issue without coming to any real decision.

The others don't fit mainly because of dates. Hitler's invasion of Poland was in 1939. His takeover of Czechoslovakia (the rest of it after he has already gained the Sudetenland via diplomatic channels) was done a year earlier in 1938. And the Soviet invasion of Finland was during the Winter War in 1939 -- two months after they had invaded Poland.

The League of Nations actually bared some teeth this time around, expelling the Soviets from the organization, though it didn't really accomplish anything. To the Soviets by the time this happened, it was probably like being kicked out of a club in which they were members of out of pity.