Assume the existence of a Building class. Define a subclass, ApartmentBuilding that contains the following instance variables: an integer, numFloors, an integer, unitsPerFloor, a boolean, hasElevator, a boolean, hasCentralAir, and a string, managingCompany containing the name of the real estate company managing the building. There is a constructor containing parameters for the initialization of the above variables (in the same order as they appear above). There are also two methods: the first, getTotalUnits, accepts no parameters and returns the total number of units in the building; the second, isLuxuryBuilding accepts no parameters and returns true if the building has central air, an elevator and 2 or less units per floor.