The English idiom"（ ）" means "so

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”。