All client computers in a company’s network environment run Windows 8. A client computer
has two internal hard disk drives. The hard drives are configured as shown in the following table.

You are choosing a backup destination for drive C.
You have the following requirements:
Ensure that the backup file is available if drive C fails.
Ensure that the backup file can be accessed by other computers on the network.
Support the backup of multiple system images.
You need to select a backup destination that meets the requirements.
Which destination should you select?

A.
shared network folder

B.
drive D

C.
multiple DVDs

D.
external hard drive

Explanation:
Shared network folder will only support one system image:

That applies to internal / external disks:

http://windows.microsoft.com/en-us/windows7/Back-up-your-programs-system-settingsandfiles
Keeping different versions of system images:
If you’re saving your system images on an internal or external drive, or on CDs or DVDs, you
can keep several versions of system images.
On internal and external hard drives, older system images will be deleted when the drive
runs out of space. Conclusion is to use external HDD and share it over the network.