采用ADO完成对“教学管理.mdb”文件中“学生表”的学生年龄都加1的操作，程序空白处应填写的是______。
Sub SetAgePlus()
Dim cn As New ADODB.Connection
Dim rs As New ADODB.Recordset
Dim fd As ADODB.Field
Dim strConnect As String
Dim strSQL As String
Set cn=CurrentProject.Connection
strSQL="Select年龄from学生表"
rs.Open strSQL，cn，adOpenDynamic，adLockOptimistic，adCmdText
Setfd=rs.Fields("年龄")
Do While Not rs.EOF
fd=fd+1
______
rs.MoveNext
Loop
rs.Close
cn.Close
Set rs=Nothing
Set cn=Nothing
End Sub

A．rs.Edit
B．rs.Update
C．Edit D．Update