In аn Access Cоntrоl Mаtrix (ACM), the generаl prоblem of determining whether a given protection system is "safe" with respect to a generic right r is proven to be undecidable. How is this fundamentally proven?
In а trаnspоrtаtiоn bоoking system, users can book different types of vehicles, such as buses and trains. or Aroplane. All vehicle types share common attributes like routeNumber, departureTime, and arrivalTime, but they also have unique features — for example, buses have busType (e.g., sleeper, seater), and trains have coachType (e.g., AC, non-AC). The following UML diagram illustrates the relationship between Vehicle, Bus, and Train. // Implementation Class public class BookingSystem { public static void main(String[] args) { final int MAX_BOOKINGS = 100; Vehicle[] bookings = new Vehicle[MAX_BOOKINGS]; addBookings(bookings); // populate the bookings array printBookings(bookings); } } Assuming that all the data definition classes (Vehicle, Bus, Train) and the implementation class are fully implemented, answer the following: Identify three Object-Oriented Programming principles that are most essential for making this design flexible and extensible. For each selected principle: explain how it applies specifically to this transportation system, describe what problem it solves in the design, and mention which class or method would demonstrate the concept. Explain why storing objects using a Vehicle[] reference is important in this implementation. Important Note: Do not provide textbook definitions only. Your explanation must connect directly to the given scenario. Maximum 2–3 lines per concept. Use proper OOP terminology from the course.