In a Splunk indexer cluster deployment, the recommended best practice is to install and run the Monitoring Console (MC) on the cluster master node. The cluster master is the central point of administration and coordination for all peer nodes (indexers) within the cluster. Hosting the MC on the cluster master provides the most comprehensive and direct visibility into the health, status, and performance of the entire indexer tier, including replication, bucket status, and peer connectivity, without impacting production search workloads.

A. Deployer sharing with master cluster: The deployer's primary role is to manage and distribute configurations to search head cluster members, not to monitor the indexer cluster's operational state.

B. License master that has 50 clients or more: The number of licensed clients is irrelevant to the architectural placement of the Monitoring Console. The decision is based on operational visibility and performance, not licensing metrics.

D. Production Search Head: Installing the MC on a production search head is strongly discouraged as it can consume significant resources, potentially degrading search performance for end-users.

1. Splunk Enterprise Documentation, Monitoring Splunk Enterprise, "Set up the monitoring console in a distributed deployment". In the table under "Which instance should host the monitoring console?", for the "Indexer cluster" deployment type, the recommended location is explicitly stated as the "Cluster master".

2. Splunk Enterprise Documentation, Managing Indexers and Clusters of Indexers, "The role of the master node". This section describes the master node's central function in managing the entire cluster, which logically makes it the ideal location for the monitoring tool that oversees the cluster's health.