The principle states that agreements relating to prohibited items, such as liquor, do not exist in the eyes of law. A agreed to sell liquor to B but failed to supply it. Let's check whether B has any legal remedy against A under this principle.
Since the agreement itself does not exist in the eyes of law due to its illegal subject matter, B has no legal ground to act against A for failing to supply the liquor.
Therefore, the correct answer is B cannot bring any legal action against A.
The principle can be read as a conditional rule: if the subject matter of an agreement is a prohibited item, then that agreement does not exist in the eyes of law at all. Liquor is named directly as such a prohibited item. A and B entered into an agreement for the sale of liquor, and A then failed to supply the agreed quantity. Before deciding who can do what, we need to see whether this rule's condition is satisfied here.
Since liquor is a prohibited item, the rule's condition is triggered and the agreement is treated as never having existed in law, so neither party, and B in particular, has any legal action available over its non-performance.
Therefore, the correct answer is B cannot bring any legal action against A.