Answer:
b) A RAID structure is primarily used to ensure higher data reliability,
Step-by-step explanation:
A set of hard disks configured as a RAID (Redundant Array of Independent Disks) , even is composed by several separate disk units, in their different configurations (RAID 0, 1, 2 or 5 being the more usual) behave like it were a single logical unit.
The information to be stored is divided in blocks (at a byte or bit level) and stored in several disks instead of a single one.
Depending on the type of RAID used , the information (except for RAID 0) is mirrored or encoded in a redundant fashion, so if eventually a disk drive fails, the remaining disks can be used in order to reconstruct the lost information.
So, the main purpose of a RAID array is to be able to retrieve the stored data in the event of a disk failure, which ensures higher data reliability.