Final answer:
The usual command on a forwarder to create a deployment server polling is 'splunk create deploypoll SERVER:PORT'.
Step-by-step explanation:
The usual command on a forwarder to create a deployment server polling is splunk create deploypoll SERVER:PORT. This command is used to create a new deployment server polling on a forwarder, allowing it to communicate with the deployment server. The other options listed are not valid commands for creating a deployment server polling.