You wish to upgrade the IOS of a router without removing the image currently installed.What command will display the amount of memory that is being used by the current IOS image and whether there is enough room available to hold both the current and new images?（）

• A、Router# show version
• B、Router# show flash
• C、Router# show memory
• D、Router# show buffers
• E、Router# show running-config
• F、All of the above