下列程序的执行结果为()。 Private Sub Commandl_Click(
题型：单项选择题
问题：
下列程序的执行结果为()。 Private Sub Commandl_Click() Dim s1 As String ,s2 As String s1= "abcd" Call Transfer(sl，s2) Print s2 End Sub Private Sub Transfer (ByVal xstr As String，ystr As String) Dim tempstr As String ystr=tempstr End Sub
A． dcba
B． abdc
C． abcd
D． dabc