You are upgrading your Cisco router IOS from a TFTP server over the network. The upgrade procedure is stopped and you are prompted to erase the current flash contents before continuing. What is most plausible reason for this? （）

• A、There is insufficient room for more than one image.
• B、The router has detected a copy of the current software image on the TFTP server.
• C、The file can be relocated and not compressed.
• D、The image to load is a binary executable file.