A Barbershop Quartet is a group of four singers: a lead, a tenor, a bass, and a baritone.  These four singers harmonize to produce a purely American form of music developed in the 19th century.  Consider the incomplete class definitions below.   public class BarberShopQuartet {    public BarberShopQuartet()    {       Tenor highSinger = new Tenor();       Baritone bari = new Baritone();       Lead melody = new Lead();       Bass lowSinger = new Bass();       System.out.println(“Quartet created.”);    } } ______________________________________________________________________________   public class Singer {    public Singer()    {       System.out.println(“Singing...”);    } } ______________________________________________________________________________   public class Tenor extends Singer {    public Tenor()    {       System.out.println(“Singing...the high notes”);    } } ______________________________________________________________________________   public class Baritone extends Singer {    public Baritone()    {       System.out.println(“Singing...harmonizing with the lead”);    } } ______________________________________________________________________________       public class Lead extends Singer {    public Lead()    {       System.out.println(“Singing...the melody and providing the    emotion”);    } } ______________________________________________________________________________   public class Bass extends Singer {    public Bass()    {       System.out.println(“Singing...the very low notes”);    } } Which of the following IS-A, HAS-A relationships is true?   A. A Baritone has-a BarberShopQuartet.   B. A Singer has-a Lead.   C. A BarberShopQuartet is-a Singer.   D. A Singer has-a BarberShopQuartet.     E. A Tenor is-a Singer.

A Barbershop Quartet is a group of four singers: a lead, a tenor, a bass, and a baritone.  These four singers harmonize to produce a purely American form of music developed in the 19^th century.  Consider the incomplete class definitions below.

public class BarberShopQuartet

{

   public BarberShopQuartet()

   {

      Tenor highSinger = new Tenor();

      Baritone bari = new Baritone();

      Lead melody = new Lead();

      Bass lowSinger = new Bass();

      System.out.println(“Quartet created.”);

   }

}

______________________________________________________________________________

public class Singer

{

   public Singer()

   {

      System.out.println(“Singing...”);

   }

}

______________________________________________________________________________

public class Tenor extends Singer

{

   public Tenor()

   {

      System.out.println(“Singing...the high notes”);

   }

}

______________________________________________________________________________

public class Baritone extends Singer

{

   public Baritone()

   {

      System.out.println(“Singing...harmonizing with the lead”);

   }

}

______________________________________________________________________________

public class Lead extends Singer

{

   public Lead()

   {

      System.out.println(“Singing...the melody and providing the   

emotion”);

   }

}

______________________________________________________________________________

public class Bass extends Singer

{

   public Bass()

   {

      System.out.println(“Singing...the very low notes”);

   }

}