As the Administration Guide Volume 1 expressed in the section of Storage Units Consideration it shows us that BasicDisk can not be selected directly but if we put them into a storage unit group It Can be assigned in the Life Cycle Policy but I can not doit either.
6.4.4 BasicDisk Storage Units in Storage Unit Groups
A Storage Unit Group that contains just one BasicDisk Storage Unit will behave as a BasicDisk
Storage Unit Group. Although Storage Lifecycle Policies do not work with BasicDisk Storage Units
there are no checks in the Storage Destination set up to prevent you from selecting an Storage
Unit Group that contains a BasicDisk. Care should be taken when using Storage Unit Groups in
Storage Destinations to ensure that there are no BasicDisk Storage Units within the Storage Unit