Your network contains a server named Server1 that has the Hyper-V server role installed.
Server1 hosts a virtual machine (VM) named VM1 that runs Windows Server 2003 Service Pack 2 (SP2).
VM1 is configured to use a 127-GB dynamically-expanding virtual hard disk (VHD).
You need to add 500 GB of disk space to VM1.
The solution must minimize the amount of downtime for VM1.
What should you do?

A.
Increase the size of the VHD drive.

B.
Convert the VHD to a fixed-size disk.

C.
Add a new VHD drive to a SCSI controller.

D.
Add a new VHD drive to an IDE controller.

Explanation:
Dynamic virtual machine storage.
Improvements to virtual machine storage include support for hot plug-in and hot removal of the storage on a SCSI controller of the virtual machine. By supporting the addition or removal of virtual hard disks and physical disks while a virtual machine is running, it is possible to quickly reconfigure virtual machines to meet changing requirements. Hot plug-in and removal of storage requires the installation of Hyper-V integration services (included in Windows Server 2008 R2) on the guest operating system.
Source: http://technet.microsoft.com/en-us/library/dd446676.aspx