Comprehensive and Detailed 1

The fundamental principle of DRY (Don't Repeat Yourself) in Apex development dictates that logic used in multiple places should be centralized. For API integrations, this typically invo2lves creating a Utility or Service Class (Option A).

This class handles the common 'plumbing' of the integration:

Retrieving Named Credentials.

Setting headers (Content-Type, Timeout).

Standardizing error handling and logging.

Serializing and deserializing JSON payloads.

By invoking this central class from various triggers, batch jobs, or controllers, the developer ensures that any change to the API (such as a version update or header change) only needs to be made in one place. Option B leads to 'class sprawl' and duplicate boilerplate code. Option C is incorrect as Static Resources cannot contain executable Apex code. Option D is the definition of poor maintainability.