What caused Germans to start taking Adolf HIter and his messege seriously?

more than anything it was the fact that the country was in an economic crisis brought about more by the Allied powers in WWI than the world wide depression that was going on at the time. Germans could not afford basic necessities and Hitler offered an answer to that by reinvigorating industry which we now know was his war machine. If I had to guess, I'd go with B, but he was skilled at speeches and the Soviets always a threat until Hitler signed a non aggression pact with them before the war.