javascript - Angularjs: How to include empty option in select when using ng-option -

How can I add empty options in the beginning when I provide a predefined list of options to use ng-option in which Is not a blank included?

Select an example in Z

  (ng-model = "property.Value", ng-option = "item. Just select an option with an empty value in the property.) "   
 
 
 Choose  
  (ng-model = "property.Value", ng-option = "item.Value item. Property.name in item.Choices") option (value = "" )   
 Here is an example -