Valentine, Holiday, and Birthday inherit from the class Card. In order for the following code to be correct, what type must the reference variable card be? card = new Valentine( "A", 14 ) ; card.greeting(); card = new Holiday( "B" ) ; card.greeting(); card = new Birthday( "C", 12 ) ; card.greeting();
Explanation:The reference has to be of the same type of the class. In this case, there are many diferent classes and the common one is Card, as all inherit from it.