设有以下函数过程Private Function Fun（a() as integer,b as string）as integer ……End Function若已有变量声明：Dim x(5) as Integer,n as Integer ,ch as string则下面正确的过程调用语句是（ ）

A．x(0)=Fun(x,”ch”)

B．n=Fun(n,ch)

C．call Fun x,”ch”

D．n=Fun(x(5),ch)