5. [25 points] Using your choice of C# or Java, define a class for a phone. A phone object should have 3 attributes: a name, a model, and an operating system. Your class should have constructors, setters (mutators), and getters (accessors), or properties (C#) for the attributes, and override object methods for equals and toString. Two phones are considered equal only if the name, model, and operating system are equal.