窗体上有一个名称为Text1的文本框和—个名称为Command1的命令按钮。要求程序运行时，单击命令按钮，就可把文本框中的内容写到文件out.txt中，每次写入的内容附加到原有内容之后。下面能够正确实现上述功能的程序是______。

A. Private Sub Command1_Click() Open "out.txt" For Input As#1 Print #1,Text1.Text Close #1 End Sub
B. Private Sub Command1_Click() Open "out.txt" For Output AS #1 Print #1,Text1.Text Close #1 End Sub
C. Private Sub Command1_Click() Open "out.txt" For Append As #1 Print #1,Text1.Text Close #1 End Sub
D. Private Sub Command1_Click() Open "out.txt" For Random As #1 Print #1,Text1.Text Close #1 End Sub