A good answer might be:

No---just one could have be used for each object in succession (assuming that the program does no more than is shown.)

Polymorphism means "having many forms." In Java, it means that a single variable might be used with several different types of related objects at different times in a program. When the variable is used with "dot notation" variable.method() to invoke a method, exactly which method is run depends on the object that the variable currently refers to. Here is an example:

. . . . // class definitions as before public class CardTester { public static void main ( String[] args ) throws IOException { Card card = new Holiday( "Amy" ); card.greeting(); //Invoke a Holiday greeting() card = new Valentine( "Bob", 3 ); card.greeting(); //Invoke a Valentine greeting() card = new Birthday( "Cindy", 17 ); card.greeting(); //Invoke a Birthday greeting() } }

QUESTION 13:

What will the program write?