To add Time Machine data access to a Nutanix cluster, the first step is to register the cluster in NDB. This will allow NDB to discover and manage the databases and snapshots on the cluster. You can register multiple Nutanix clusters in NDB using the Add Cluster option in the NDB settings page. You can also specify the cluster role, such as source, target, or both, depending on the data access and replication needs. Enabling or disabling multi-cluster in NDB is not the first step, as this is a global setting that affects the entire NDB instance. Deleting the TM data from the source database is not the first step, as this will remove the data protection and availability of the database. References:
* Nutanix Database Management & Automation Training Course, Module 6: Managing NDB Multi-Cluster, Lesson 1: NDB Multi-Cluster Overview, Slide 5: Registering Nutanix Clusters
* Nutanix Certified Professional - Database Automation (NCP-DB) 5 Exam, Section 6: Administer an NDB Environment, Objective 6.4: Apply procedural concepts to add Nutanix clusters to NDB

Creating a point-in-time clone is the correct nondisruptive recovery action. NDB Time Machine combines snapshots with captured Oracle archive logs to construct a database at a selected recoverable timestamp.
Choosing 2:10 PM replays the available logs only through that moment, which precedes the 2:15 PM DROP TABLE. Because the result is a separate clone, the production database remains online and unchanged while the administrator extracts and returns the missing table data. A restore would rewind the source database itself and could interrupt or overwrite its current state. Refresh applies to an existing clone rather than creating the required recovery copy, while a Software Profile defines database software instead of transactional content.
Nutanix's Oracle cloning guidance therefore supports option D. Nutanix Oracle clone documentation

Before patching several Nutanix database server VMs using the "Patch OS now" feature in NDB, the administrator must configure a Repository. A repository (e.g., a custom patch repository or Nutanix-provided source) contains the OS updates or patches (e.g., for Windows or Red Hat-based systems). NDB requires this repository to be specified to fetch and apply the patches, ensuring the database VMs are updated from a validated source.
Other options are unrelated to patching:
B). Active Directory Access: Used for authentication, not patching.
C). pulse: Refers to Nutanix Pulse for support, not patch configuration.
D). An SMTP Server: Configured for alerts, not patching.
Thus, the verified answer is A, reflecting the patching prerequisite.
Official Nutanix Database Automation References
Nutanix Database Management & Automation (NDMA) course, Module 6: Maintenance and Patching, Lesson 6.3: Creating Maintenance Plans.
Nutanix Certified Professional - Database Automation (NCP-DB) v7.5Knowledge Objectives, Section 6:
Optimize NDB Solutions, Objective 6.3: Manage Maintenance Plans (applicable to v7.5).
Nutanix NDB Administration Guide: "Configuring Patch Repositories" section.

NDB alert policies are enabled by default and may be disabled when an administrator does not want a particular policy to generate alerts. The policy can later be enabled again, allowing alert generation to resume without recreating the policy or changing the monitored resource. This preserves the policy definition while suppressing unwanted notifications and events. NDB also supports operations such as configuring retention and resolving alerts, but those are separate alert-management functions. Pause is terminology associated with other scheduled processes, not the alert-policy control. Publish applies to objects such as software profile versions, and deletion is not the standard control exposed for built-in NDB alert policies. Consequently, Disable is the valid action among the choices. The supported behavior is described in Nutanix's Disabling or Enabling Alert Policies procedure.

According to the Nutanix Database Automation (NCP-DB) learning documents, Nutanix Era supports x509 certificates in Base-64 encoded PEM format1. This format is used when an administrator needs to replace the default Nutanix self-signed certificates in Era1.