Which four are true？（）

• A、 Has-a relationships should never be encapsulated.
• B、 Has-a relationships should be implemented using inheritance.
• C、 Has-a relationships can be implemented using instance variables.
• D、 Is-a relationships can be implemented using the extends keyword.
• E、 Is-a relationships can be implemented using the implements keyword.
• F、 An array or a collection can be used to implement a one-to-many has-a relationship.
• G、 The relationship between Movie and Actress is an example of an is-a relationship.