The author claims that a translation’s inability to remain faithful to the text’s meaning and the author’s style is what makes it flawed. (A) tells us that translations should not remain faithful to these things, so it doesn’t help justify the author’s conclusion.

This gets the argument’s logic backwards. We need a principle that shows that since translations are imperfect compromises between meaning and style, they cannot be better than a flawed approximation of original works.

Irrelevant. We know that the two goals—meaning and style—cannot be fully reconciled; it doesn’t matter how balanced the compromise between them is.

Since any translation will compromise between faithfulness to the meaning of the text and faithfulness to the author’s style, (D) justifies the claim that any translation will be at best a flawed approximation of the original work.

This is redundant. We already know that translations must always compromise between these two things. In order to justify the conclusion, we need a principle that confirms that this fact means that a translation can be no more than a flawed approximation.