My uncle Cassidy gives me money! Pigs might fly if they had wings! 从文化传真角度来说，哪个译文更为恰切？

My uncle Cassidy gives me money! Pigs might fly if they had wings! 从文化传真角度来说，哪个译文更为恰切？
A.我的卡西迪叔叔会给我钱？那猪也会长翅膀飞上天啦！
B.我的卡西迪叔叔会给我钱？除非公鸡会下蛋！
正确答案：我的卡西迪叔叔会给我钱？那猪也会长翅膀飞上天啦！