Option Explicit
Private Sub Worksheet_Change(ByVal Target As Range)
Dim colA As Long
Dim colB As Long
Dim colC As Long
Dim colD As Long
Dim ColDa As Variant
If Target.Address <> "$F$1" Then Exit Sub
Range("A:A").ClearContents
Select Case Target.Value
Case Is = "colA"
colA = Sheets("Sheet2").Range("A" & Rows.Count).End(xlUp).Row
Sheets("Sheet2").Range("A1:A" & colA).Copy Sheets("Sheet1").Range("A100").End(xlUp).Offset(1, 0)
Case Is = "colB"
colA = Sheets("Sheet2").Range("B" & Rows.Count).End(xlUp).Row
Sheets("Sheet2").Range("B1:B" & colA).Copy Sheets("Sheet1").Range("A100").End(xlUp).Offset(1, 0)
Case Is = "colC"
colA = Sheets("Sheet2").Range("C" & Rows.Count).End(xlUp).Row
Sheets("Sheet2").Range("C1:C" & colA).Copy Sheets("Sheet1").Range("A100").End(xlUp).Offset(1, 0)
Case Is = "colD"
colA = Sheets("Sheet2").Range("D" & Rows.Count).End(xlUp).Row
Sheets("Sheet2").Range("D1:D" & colA).Copy Sheets("Sheet1").Range("A100").End(xlUp).Offset(1, 0)
End Select
End Sub