Disk configuration after virtualizing a phyiscal server to a Hyper-V VM

Hi,
I virtualized a physical server to Hyper-V using the Disk2vhd utility.
The physical server had a C:\ and another larger drive but I only selected the C drive in the Disk2vhd utility.
After the conversion finished and I restored the vhdx to create a new hyper-v vm, Windows explorer and disk management are showing different disk configs.

Please can someone explain why the C: drive in Explorer differs to the disk management screen?
Is there anyway I can release the unused disk space displayed in disk management because the Hyper-V VM only needs the C drive
Disk-Management.PNG
Explorer.PNG