The growth of Mussolini's Fascist movement was aided by?

The growth of Mussolini's Fascist movement was aided by

a. the inability of the parliamentary parties to conduct an adequate foreign policy.

b. popular, nationalistic resentment toward Italy's treatment
ollowing World War I.

c. crop failures in 1920 and 1921.

d. economic cooperation between Italy, Germany, and the Soviet Union.

B, and some other things. Fascist squads were violently anti-labor union. Rich landowners and factory owners liked this and gave the Fascists economic and political support. Also, Mussolini was a clever speaker and writer who knew how to play to his audience, and how to explain away contradictions with things he said earlier (he started out in politics as a pacifist anarchist!).
He was also aided by the fact that Italians as a whole felt that their government, a "liberal" government in that it had a popularly elected parliament, was a failure. People were ready to entertain radical solutions, including syndicalism and socialism. Stirring up the mess was irredentism, the movement to bring all the Italian people of the Adriatic basin into one government (irredentism was common all through Europe at the time). In addition the economy was unstable and Mussolini promised stability and prosperity. ( He delivered on stability but failed to make Italy prosperous.)

B, definitely

e. Inaction by the population at large to come to grips with the known dangers inherent in such a regime. Sound familiar? :))