To maximize search efficiency in Splunk, it is crucial to filter the data as early as possible to reduce the amount of data being processed in subsequent commands. From the provided options, answer C is the correct choice. The command sequence in option C starts by filtering the data using the index, sourcetype, and customer before performing the lookup and stats operations. This ensures that only relevant data is processed, significantly enhancing efficiency. Additionally, option C arranges the commands in an optimized order by prioritizing the customer filter, applying the lookup, filtering by vip_status, aggregating data with stats, and finally displaying the required fields using the table command.