After reloading a router, you issue the dir command to verify the installation and observe that the image file
appears to be missing. For what reason could the image file fail to appear in the dir output?

A.
The secure boot-image command is configured.

B.
The secure boot-config command is configured.

C.
The confreg 0x24 command is configured.

D.
The reload command was issued from ROMMON.

Explanation:
BD
#secure boot-image
This command enables or disables the securing of the running Cisco IOS image. Because this command has
the effect of “hiding” the running image, the image file will not be included in any directory listing of the disk.
Source: http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/security/s1/sec-s1-cr-book/sec-crs1.html#wp3328121947