Final answer:
The hallmark of envisioning program components as objects that are similar to concrete objects in the real world is Object-Oriented Programming (OOP).
Step-by-step explanation:
The hallmark of envisioning program components as objects that are similar to concrete objects in the real world is Object-Oriented Programming (OOP). In OOP, program components are represented as objects that have properties (attributes) and behaviors (methods), just like real-world objects.
For example, in an online shopping program, a product object can have properties like price and name, and behaviors like adding to cart and checking out. By using OOP, programmers can create code that is modular, reusable, and easier to maintain.