一组数据为2、3、5、7、3、4，对于这组数据，下列说法错误的是（　　）

A．平均数是4

B．极差是5

C．众数是3

D．中位数是6

A client with a retinal detachment does not understand what happened to his eye and asks the nurse's explanation. Which of the following would be the nurse's best response to describe the pathology of retinal detachment

A．"The optic nerve is damaged when it is exposed to vitreous humor. "

B．"A tear in the retina permits the escape of vitreous humor from the eye. "

C．"The two layers of the retina separate, allowing fluid to enter between them. "

D．"Retinal injury produces inflammation and edema that increase intraoeular pressure. "