What factors led to the beginning of World War II in Europe?

A.various independence movements in Serbia against Austria-Hungary

Bthe rise of aggressive nationalism among some of the nations defeated in World War I
Cthe rise of communism in Soviet Russia, which was seen as a threat by many European nations

D.rising competition among European powers for colonies and trading posts in Africa and Asia


You can pick multiple

Verified Answer :

B. the rise of aggressive nationalism among some
of the nations defeated in World War I 
B.
the rise of aggressive nationalism among some of the nations defeated in World
War I.
Germans suffered under a bad economy where one of the causes was the
massive reparations that they had to pay.
Feelings of resentment grew among the citizens and Adolf Hitler used
that to fuel an aggressive form of nationalism that would let to military
build-up and eventually led to WW II.