The English idiom"（ ）" means "something useless and unwanted but

The English idiom"（ ）" means "something useless and unwanted but big and costly".
A、white elephant
B、flesh and blood
C、an apple of discord
D、​fly in the ointment
【正确答案】：A
【题目解析】：white elephant表示“昂贵而无用的东西”，flesh and blood表示“亲属”，an apple of discord表示“纷争之源，不和之源”，fly in the ointment表示“美中不足”。