In Splunk Cloud, you can install apps via self-service, which allows you to install certain approved apps without involving Splunk Support. This self-service capability is provided for apps that have already been vetted and approved for use in the Splunk Cloud environment.
* Option Atypically requires support involvement because premium apps often need licensing or other special considerations.
* Option Bmight involve the Request Install button, but some apps might still require vetting or support approval.
* Option Dis incorrect because apps that have not gone through the vetting process cannot be installed via self-service and would require Splunk Support for evaluation and approval.
Splunk Documentation Reference: Install apps on Splunk Cloud