If the Combo Box AddressBox Contains a List of Strings

If the combo box addressBox contains a list of strings, why is the returned value of getSelectedItem method in the following code cast to String?
String selectedAddress;
SelectedAddress = (String) addressBox.getSelectedItem() ;

A) This is not necessary.
B) Because the syntax of the method requires it
C) It makes the program more readable.
D) Because the return type of the method is an Object