Comprehensive and Detailed Step by Step Explanation:
Understanding the Scenario: The question is about ensuring that an organization retains control over its encryption keys. It focuses on different key storage and management methods.
Analyzing the Answer Choices:
A: Encrypting using a key stored in an on-premises hardware security module (HSM): This is the best option for maintaining complete control over encryption keys. An HSM is a dedicated, tamper-resistant hardware device specifically designed for secure key storage and cryptographic operations. Storing keys on-premises within an HSM ensures the organization has exclusive access.