题目内容：
The definition of Robertsonian translocation is （）
A.The two long arms of two separate acrocentric chromosomes are lost.
B.The two short arms of two separate acrocentric chromosomes are fused. The long arms are lost.
C.The two long arms of two separate metacentric chromosomes are fused. The short arms are lost.
D.The two long arms of two separate acrocentric chromosomes are fused. The short arms are lost.
参考答案：