Use a ComboBox control. Add the country names to the Items(Collection) property. Add "Select country" to the Text property.
User clicks the down arrow and makes a selection. If no selection was made, the value of the SelectedIndex is -1.
In your code, use a Select Case block for the text of the Combobox items, and assign the option value you require after each case, which would be the text of the selected item - the country.
For example:
Select Case cboCountry.Text
Case Austria
optionval = 01143
'etc