You plan to create a storage account named storage1 with these settings: Performance: Standard; Replication: ZRS; Access tier (default): Cool; Hierarchical namespace: Disabled. To allow Account kind to be set to BlockBlobStorage, which setting must you change first?

The BlockBlobStorage account kind only supports Premium performance. Therefore, to select BlockBlobStorage as the account kind, you must first change the Performance setting from Standard to Premium. Changing Replication, Access tier (default), or Hierarchical namespace does not directly enable the BlockBlobStorage account kind. While these settings are configurable for BlockBlobStorage accounts, they are not prerequisites for selecting that account kind. The core dependency for BlockBlobStorage is the Premium performance tier.