To extend Partition1, you need to first extend the virtual disk that it is located on. The question states that Disk 1 uses a mirrored layout, which means it is a part of a storage pool. To extend the virtual disk, you should go to the Storage Pools page in Server Manager and use the options available there to extend the virtual disk. Once the virtual disk is extended, you can then go to Disk Management and extend the volume for Partition1 to utilize the additional space. Therefore, the correct answer is C. From the Storage Pools page in Server Manager, extend a virtual disk.