The correct option is Compliance Manager.

Compliance Manager is designed to help organizations assess and manage regulatory requirements and it centralizes assessment templates, control tracking, and evidence management. It lets teams record assessment results and upload customer evidence and supporting documentation which auditors can review, so it fits a workflow that needs retained regulated records and archived experiment artifacts for audit purposes.

Microsoft Service Trust Portal provides Microsoft produced compliance reports and certifications for customers to download but it is mainly a repository of Microsoft audit artifacts and does not provide an operational compliance management platform for tracking controls or customer evidence.

Microsoft Defender for Cloud focuses on cloud security posture management and threat protection for workloads and it helps detect and remediate security issues but it is not intended to be used as a compliance documentation and evidence management solution.

Azure Purview is primarily a data governance and data catalog service that offers discovery, classification, and lineage and it helps with data governance and retention policies. It is not the central tool for managing compliance assessments and storing audit evidence. Note that Azure Purview has been rebranded to Microsoft Purview which is the current product name you may see on newer materials.

Full AWS Practitioner Certification Question