Which of the following is a valid file name for a Cisco IPS 6.0 system image?

Which of the following is a valid file name for a Cisco IPS 6.0 system image?

A.
IPS-K9-cd-11-a-6.0-1-E1.img

B.
IPS-K9-pkg-6.0-sys_img.sys

C.
IPS-4240-K9-img-6.0-sys.sys

D.
IPS-4240-K9-sys-1.1-a-6.0-1-E1.img