[单项选择题] 单击一次窗体之后，下列程序代码的执行结果为______ 。 Private Sub Command1_ Click()Dim a As Integer, b As Integer,

[单项选择题] 单击一次窗体之后，下列程序代码的执行结果为______ 。 Private Sub Command1_ Click()Dim a As Integer, b As Integer, c As Integera = 1: b = 2: c = 4Print Value(a, b, c) End Sub Function Num(x As Integer, y As Integer, z As Integer)Num = x * x + y * y + z * z End Function Function Value(x As Integer, y As Integer, z As Integer)Value = Num(x, y, z) + 2 * x End Function

A．21

B．23

C．19

D．35