单击命令按钮时，下列程序代码的执行结果为( )。 Private Function FirProc(x As Integer,y As Integer,z As Integer) 　　　FirProc=2*x+y+3*z End Funcfion Private Function SecProc(x As Integer,y As Integer,z As Integer) 　　　SecProc=FirProc(z，x，y)+x End Funcfion Private Sub Command1_Click() Dim a As Integer Dim b As Integer Dim c As Integer a=2 b=3 c=4 Printf SecProc(c,b,a) End Sub

A．21

B．19

C．17

D．34