Which of the following code should we use to define a root route?

A)  Router = Backbone.Route.extend({ route: { ": 'index' }, index: function(){ $(document.body).append("root index route"); } });
B)  Router = Backbone.Router.extend({ routes: { ": 'index' }, index: function(){ $(document.body).append("root index route"); } });
C)  Route = Backbone.Router.extend({ route: { ": 'index' }, index: function(){ $(document.body).append("root index route"); } });
D)  All of the above.

Correct Answer :   Router = Backbone.Router.extend({ routes: { ": 'index' }, index: function(){ $(document.body).append("root index route"); } });