Multiple Select Cases - VBA

If you remove the trailing spaces off of the data that makes up your drop down values then the below will work:

Private Sub Worksheet_Change(ByVal Target As Range)
    Dim rRow As Long
    
    If Not Intersect(Target, Range("F15,F53")) Is Nothing Then
        If Target.Address = "$F$15" Then
            Rows("17:45").Hidden = True
            rRow = Range("C17:C45").Find(Target.Value).Row
            Rows(rRow & ":" & rRow + 3).Hidden = False
        ElseIf Target.Address = "$F$53" Then
            Rows("55:83").Hidden = True
            rRow = Range("C55:C83").Find(Target.Value).Row
            Rows(rRow & ":" & rRow + 3).Hidden = False
        End If
    End If
End Sub