Visual Basic for Applications (VBA) Choice Questions

Which two sets of values are printed by this function and sub?

Function GetVitals(ID As Long, Age As Long, Optional Weight As Long) As String
    GetVitals="ID=" & ID &"Age=" & Age & "Weight=" & Weight
End Function
Sub ShowVitals()
    Dim ID As Long, Age As Long,Weight as Long
    Debug.Print GetVitals(ID:=5,Age:=20)
    Debug.Print GetVitals(ID:=6,Age:=25,Weight:=130)
End Sub

:

ID=5 Age = 20 Weight=
ID=6 Age = 25 Weight=130

:

ID=5 Age = 20 Weight=0
ID=6 Age = 25 Weight=130

:

ID=5 Age = 20 Weight=Null
ID=6 Age = 25 Weight=130

:

ID=5 Age = 20
ID=6 Age = 25 Weight=130