The question requires an efficient, scalable solution for image processing and workflow monitoring with minimal effort. Option C is correct because Google Cloud Workflows is designed for serverless orchestration of tasks, allowing easy automation of resizing, cropping, and watermarking as steps in a workflow. Cloud Logging integrates naturally for monitoring workflow execution logs. Other options have drawbacks: Option A uses Dataproc (for big data, not monitoring) and Cloud Composer (overly complex for simple workflows). Option B includes Apigee (unnecessary for the requirements) and lacks orchestration. Option D relies on Cloud Build (CI/CD tool, not event-driven for image processing) and Cloud Functions without proper orchestration. Workflows (C) provides the simplest, most scalable approach.