Which Three of the Following Will Return an Instance of a Resource

Multiple Choice

Which three of the following will return an instance of a resource model? (Choose three)

A) Mage::getResourceModel ('customer/customer') ;
B) Mage::getResourceSingleton ('customer/customer') ;
C) Mage::getModel ('customer/customer') ->getResourceModel ( ) ;
D) Mage::getResourceModel ('customer/customer') ->getInstance ( ) ;
E) Mage::getModel ('customer/customer') ->getResource ( ) ;
F) Mage::getResourceModel ('customer/customer') ->getResource( ) ;