Which of the below mentioned AWS functionalities helps them to achieve this?

Explanations:

AWS MFA (Multi-Factor Authentication) is a security feature that adds an additional layer of security for accessing AWS services but does not provide database storage encryption.

AWS EBS (Elastic Block Store) encryption provides seamless encryption of data at rest and in transit for data stored on EBS volumes, making it a suitable option for secure database storage.

Multi-tier encryption with Redshift pertains to data stored in Amazon Redshift, which is a data warehouse service. It does provide encryption, but it is not specifically for general database storage needs.

AWS S3 (Simple Storage Service) server-side encryption is used for protecting data stored in S3 buckets, but it is not specifically designed for database storage solutions, making it less relevant for this scenario.