Mastering C++: A Comprehensive Quiz Based on 'Thinking in C++' 2025 - Free C++ Practice Questions and Study Guide

Upcasting is a term used in object-oriented programming, where a derived type is converted to its base type. This means that an instance of a class that inherits from a parent class can be used as an instance of the parent class. This allows for polymorphism, where a single code can be used for multiple types of objects. Option A is incorrect because it is the opposite of what upcasting means. Option B is incorrect because it is describing a different concept called dead code elimination. Option D is incorrect because it is not related to the concept of upcasting.