What lesson did European leaders learn from Hitler's invasion of
Czechoslovakia?

Hitler wanted that heavy industrial power for the German Reich, and so his expansionist plans had had Czechoslovakia as their first target of takeover since at least 1937, when he had first ordered his generals to draw up plans for a possible future military invasion.

Explanation:

hello,

the steamboat is your answer.

it seems like its the only form of transportation on the choices.