Mastering C++: 2026 All-In-One Quiz – Ace 'Thinking in C++' with Comprehensive Practice!

The class Tree shows initialization through overloading the operator<< for Tree objects. This is the correct answer because overloading the operator<< is a common way to initialize a class in C++. It allows for custom initialization of objects of a specific class and can be used to define how they are displayed or used in a program. Options A, B, and C are incorrect because they do not relate to how initialization takes place in the class Tree. Setting static variables, using friend functions, and having a specialized Tree constructor are all possible methods for defining a class, but they do not specifically demonstrate how initialization occurs.