Pulse is a built-in tool that periodically collects and sends diagnostic data to Nutanix support for proactive monitoring and troubleshooting. This data includes cluster configuration, performance metrics, and error logs, among other things. Nutanix support can use this data to identify and resolve issues before they become critical, and to provide recommendations for optimizing cluster performance.
NCC (Nutanix Cluster Check) is another tool provided by Nutanix, but it is used for performing manual health checks and diagnostics on the cluster, rather than providing proactive support.
Cluster Heart and Cluster Health are not tools provided by Nutanix, and are not relevant to this question.

Metro-Availability is a feature of Nutanix clusters that provides high availability in the case of a node failure. It requires two nodes and uses asynchronous replication between the two sites to ensure that data is replicated across the two sites in real-time. This ensures that, in the case of a node failure, the data is still available and the cluster can remain operational. Reference: https://portal.nutanix.com/page/documents/details?targetId=Platform-Administrator-Guide-v5_7:pag-metro-availability-c.html

Data Obfuscation is a feature in Pulse that helps secure a customer's private information by obfuscating the data before it is sent to Nutanix. This ensures that any data sent to Nutanix is not visible to anyone other than the customer, and helps protect sensitive data from unauthorized access or malicious actors. Reference: https://portal.nutanix.com/page/documents/details?targetId=Platform-Administrator-Guide-v5_7:pag-pulse-c.html