Choice "A" is correct. The accounting system data backup of year-end information should be stored in some kind of secure off-site location and not in any of the other listed locations.
Choice "d" is incorrect. The accounting system data backup would certainly not be stored (only) on a data backup server in the network room. What if the server crashed completely and the data could not be recovered? What if the network room burned down?
Choice "b" is incorrect. The accounting system data backup would certainly not be stored (only) in a fireproof cabinet in the data network room. The media to store the data might be more than would fit into a "cabinet" (many large corporations have hundreds of tapes of such data). The cabinet may be fireproof, but if a flood or other natural disaster hits, the cabinet may not be safe.
Choice "c" is incorrect. The accounting system data backup would certainly not be stored (only) in a locked file cabinet in the accounting department. The accounting department is not immune to fires, floods, and other natural disasters.