要想在过程Proc调用后返回形参x和y的变化结果，下列定义语句中正确的是（）。

A．Sub Proc(x as Integer, y as Intege
B．Sub Proc(By Val x as Integer, y as Intege
C．Sub Proc(x as Integer, By Val y as Intege
D．Sub Proc(By Val x as Integer, By Val y as Intege