Solution

The correct answer is Both Statement I and Statement II are correct 

Key Points

• Statement I: Subsystem models show logical grouping of objects into coherent subsystems.
• Explanation:
  • This statement is correct. Object-oriented design often involves many different objects, each with their own attributes and methods.
  • Subsystems are one way of managing this complexity by grouping related objects together.
  • A subsystem model therefore shows these groups of objects that are related and interact closely with each other.
  • For instance, in an online shopping system, all classes dealing with payment (like CreditCard, DebitCard, PayPal, etc.) could be grouped into a Payment subsystem.
• Statement II: State machine models show how objects change their states in response to events.
• Explanation:
  • This statement is also correct. In a substantial number of software applications, specifically those that deal with real-time systems, complex control systems, or certain types of business logic, objects can have different states.
  • For instance, an 'Order' object might have states like "New", "Payment Processing", "Dispatched", "Delivered", etc.
  • A state machine model represents the different states an object can have, and the ways (events or conditions) in which a transition happens from one state to another.