Which block storage volume allocates all of the physical storage specified at the time it...

A Thick provisioned LUN (Logical Unit Number) allocates all of the physical storage specified at the time it is created. In thick provisioning, the storage space is allocated upfront from the storage pool to the LUN, regardless of how much data is actually written. This ensures that the allocated space is always available for the LUN, providing predictable performance and capacity but potentially leading to less efficient use of storage resources.

References: Dell Information Storage and Management V5 course material -Dell Education