The correct answer is C. Unlock the application. Relativity's application uninstall documentation states that before deleting or uninstalling an application, you must unlock the application if necessary , and specifically notes that you can't delete a locked application . That makes unlocking the required prerequisite among the options given.
The other options are not listed as required prerequisites. There is no documented requirement to run an uninstall script from the Scripts tab, delete associated tabs first, or unlink all saved searches before uninstalling. Relativity separately documents locking and unlocking applications and states that unlocking allows editing and changes to the application. Therefore, prior to uninstalling an application from a workspace, the required step is to unlock the application .