After making changes to the router, you issue the "copy

单项选择题

After making changes to the router, you issue the "copy running-config startup-config" command to save changes. After reloading the router, the router comes up in setup mode. You again make changes, save them, and reboot. Again,the router comes up in setup mode.
What is the most likely cause of this?（）

A. The NVRAM is corrupted.
B. The boot system commands were omitted in the configuration.
C. The configuration register setting is incorrect.
D. The upgraded configuration incompatible with the hardware platform.
E. The upgraded IOS incompatible with the hardware.

CCNA(640-801)