问题详情

It is implied in the selection that the tiny bits of dust are______.
A．to prove that a criminal has been on the scene of the crime
B．to prove that a criminal has not been on the scene of the crime
C．to tell the detective what a criminal has done lately
D．to show the detective a criminal"s nose and his ears请帮忙给出正确答案和分析，谢谢！