In AngularJS, which of the following best describes the role of the factory method when defining services?

Introduction / Context:
AngularJS provides several ways to define services, including factory, service, and provider methods. Services are singleton objects that contain reusable business logic or data access code. This question focuses on the factory method and asks what role it plays when defining services in an AngularJS application.

Given Data / Assumptions:

• The framework is AngularJS, with dependency injection and modular structure.
• The term factory refers to the angular.module().factory method.
• Services created by a factory can be injected into controllers, directives, and other services.
• We want to know what the factory method is used for in this context.

Concept / Approach:
In AngularJS, a factory is a function that returns an object, function, or any value that represents the service. AngularJS calls the factory function once, caches the result, and injects that value wherever the service is requested. The key idea is that the factory method is used to create and configure a service object. The correct option must reflect this behaviour and avoid confusing it with unrelated tasks such as calculating factorials or generating random data.

Step-by-Step Solution:
1. Recall the syntax: angular.module("app").factory("myService", function() { return { sayHello: function() { return "Hello"; } }; });.2. The factory function builds an object that contains methods and data for the service.3. AngularJS injects the resulting object wherever myService is requested, making it a reusable singleton.4. Option A states that the factory method is used to create and configure a service object that can be injected into controllers and other components, which matches the actual behaviour.5. Option B restricts the role to calculating factorial values, which is just one possible use case and not the definition of the factory method.6. Option C claims that factories can only generate test data, which is incorrect as they are used in real production services.7. Option D says it generates random facts and figures without logic, which is not an accurate description of AngularJS factories.8. Therefore, Option A is correct.

Verification / Alternative check:
You can confirm by reading AngularJS documentation or by creating a simple factory that returns an object with multiple functions. Once the factory is registered, you can inject it into a controller and call its methods. The fact that this factory created object is injected wherever needed demonstrates that the factory method is used to build and configure service objects.

Why Other Options Are Wrong:
Option B is wrong because computing factorials is just an example of what a service might do, not a definition of the factory concept.Option C is wrong because services created via factories are critical parts of real applications, not only test helpers.Option D is wrong because factories can contain complex and well structured business logic, not random data generators by definition.

Common Pitfalls:
Developers sometimes confuse factory and service methods in AngularJS. While both create injectable values, a factory returns the service value directly, whereas service uses a constructor function. Another pitfall is placing too much logic in controllers instead of moving shared logic into services created by factories. Understanding the purpose of the factory method helps you organise code into modular, testable components.

Final Answer:
It is used to create and configure a service object that can be injected into controllers and other components.