以下程序运行后，单击命令按钮，窗体显示的结果是 ______。
Private Function p1(x As Integer，y As Integel，z As Integer)
p1=2*x+y+3*z
End Function
Private Function p2(x As Integer，y As Integer，z As Integer)
p2=p1(2，y，x)+x
End Function
Private SubCommandl_Click()
Dim a As Integer
Dim b As Integer
Dim c As Integer
a=2:b=3:c=4
Print p2(c，b，

A．
End SubA) 19

B．21

C．22

D．23

游客乘坐过山车，在圆弧轨道最低点处获得的向心加速度达到20 m/s²，g取10 m/s²，那么此位置座椅对游客的作用力相当于游客重力的[ ]

A．1倍  

B．2倍

C．3倍  

D．4倍