You need to upgrade the IOS of an existing router on your network. The new IOS image is located on a TFTP server that you have set up within the network. What command should you issue in order to download the new IOS version?（）
- A Router# copy tftp flash
- B Router# copy flash run
- C Router(config)# restore flash
- D Router(config)# repair flash
- E Router#copy flash tftp
- F Router# copy start flash