In object oriented programming, which list best represents the core elements or principles that define the object oriented paradigm?

Introduction / Context:
Object oriented programming is defined by several key concepts that distinguish it from purely procedural styles. Many exam questions ask for the main elements or pillars of the object oriented paradigm. Knowing these core principles helps you reason about class design and recognise whether a language or framework supports object orientation well.

Given Data / Assumptions:

• We are considering classic textbook object oriented principles.
• The question asks about conceptual elements, not specific language features like threads or memory models.
• Commonly cited pillars include encapsulation, inheritance, polymorphism, and abstraction.
• Other computer science terms such as stack or queue belong to different topics.

Concept / Approach:
Encapsulation refers to bundling data and related methods into a single unit, typically a class, and controlling access to that data. Inheritance allows new classes to be defined based on existing ones, reusing and extending behaviour. Polymorphism enables a single interface to be used for different underlying types, so that the same message can result in different behaviour depending on the actual object. Abstraction focuses on exposing essential features while hiding unnecessary details, often through well designed interfaces and class hierarchies. Together, these principles form the conceptual foundation of object oriented design.

Step-by-Step Solution:
Step 1: Review the standard list of object oriented principles that are discussed in most introductory texts.Step 2: Recognise that encapsulation, inheritance, polymorphism, and abstraction are repeatedly mentioned as the four major elements.Step 3: Compare this list with option A, which exactly contains these four terms.Step 4: Observe that options B, C, and D list concepts that belong to other areas such as compilation, data structures, or general programming constructs.Step 5: Conclude that option A is the only one that correctly represents the core object oriented elements.

Verification / Alternative check:
A quick review of object oriented programming chapters in standard books or online resources shows these four concepts grouped together as the main characteristics of object orientation. Although some authors add additional ideas such as message passing or dynamic binding, the listed four are universally recognised. The absence of these terms in the other options further confirms that they are not correct answers to this specific question.

Why Other Options Are Wrong:
Option B describes the typical stages of program execution in compiled languages, not object oriented concepts. Option C lists common data structures, which are important in algorithms and system design but do not define the object oriented paradigm. Option D mixes several unrelated programming techniques and runtime services such as recursion and garbage collection, again not matching the conceptual pillars of object orientation. Therefore these options are not correct.

Common Pitfalls:
A common pitfall is to memorise the names of the four principles without understanding how they interact. For example, misusing inheritance where composition would be better can lead to rigid designs. Another mistake is ignoring abstraction and exposing too many implementation details, which harms maintainability. Studying concrete examples of encapsulation, inheritance, polymorphism, and abstraction in real code will make these concepts more than just memorised buzzwords and will help in both interviews and practical programming.

Final Answer:
Correct answer: Encapsulation, inheritance, polymorphism, and abstraction