Oracle Autonomous Database is a fully managed cloud database service that uses machine learning to automate database administration tasks. It is designed to be "self-driving," "self-securing," and "self-repairing." This includes automating database provisioning, scaling compute and storage independently without downtime, and managing backups. Its core features include using artificial intelligence to monitor and tune workloads automatically, as well as applying security patches and updates with no service interruption. This comprehensive automation, driven by AI, directly aligns with all the capabilities mentioned in the question.

A. OCI MySQL Database Service is a managed service for MySQL, but it lacks the advanced AI-driven self-tuning and fully autonomous management capabilities characteristic of the Autonomous Database.
C. OCI Virtual Cloud Network (VCN) is a foundational networking service for creating and managing private networks in OCI; it is not a database service.
D. OCI NoSQL Database Cloud Service is a managed service for NoSQL databases. While it automates provisioning and scaling, it does not include the specific AI-based autonomous tuning features.

1. Oracle Cloud Infrastructure Documentation, "What Is Autonomous Database?": "Oracle Autonomous Database is a fully managed, preconfigured database environment... Autonomous Database handles creating the database, backing up the database, patching and upgrading the database, and growing or shrinking the database." It further describes the self-driving capabilities that automate database tuning and management.

2. Oracle Cloud Infrastructure Documentation, "Overview of Autonomous Database": "Autonomous Database is a cloud database that uses machine learning to automate database tuning, security, backups, updates, and other routine management tasks traditionally performed by DBAs." This explicitly confirms the use of machine learning (AI) for automation.

3. Oracle Cloud Infrastructure Documentation, "Overview of the MySQL Database Service": This document describes the MySQL service as a fully managed service that automates tasks like backup and recovery, but it does not mention the AI-driven, self-tuning capabilities that define the Autonomous Database.

4. Oracle Cloud Infrastructure Documentation, "Overview of the VCN": This source defines a VCN as "a customizable, software-defined network that you set up in an Oracle Cloud Infrastructure region," confirming it is a networking service, not a database.