What is the usage of Backbone.sync?

A)  When Backbone.js wants to save or read a model to the Server, it calls out a function called Backbone.sync.
B)  When Backbone wants to save or read a view to the Server, it calls out a function called Backbone.sync.
C)  When Backbone wants to save or read an event to the Server it calls out a function called Backbone.sync.
D)  All of the above.

Correct Answer :   When Backbone.js wants to save or read a model to the Server, it calls out a function called Backbone.sync.