This poem makes a mythological allusion to the greek hero, achilles. an achilles' heel refers to

anyone who was dealing with communism in soviet union in his time had an ideal picture of equality, freedom, the struggle of the working class for a better future, the success of the aristocracy's overthrow and the emancipation of subjugation.   however, anyone who would go to soviet union to see the functioning of the communist system, would be convinced that it was about sad people, about everyday bad life, about the brutal attitude of communist leaders, about ill obsession to completely exterminate every thought on aristocracy. thus, orwell wanted to show all the absurdity, the brutality of the system, the unbearable rule of suspicious morality, the ignorant people who try to play professionally.

the answers are: b. and e.