Which statement is true when you have generated RSA keys on your Cisco router to prepare for
secure device management?

A.
You must then zeroize the keys to reset secure shell before configuring other parameters.

B.
The SSH protocol is automatically enabled.

C.
You must then specify the general-purpose key size used for authentication with the crypto key
generate rsa general-keys modulus command.

D.
All vty ports are automatically enabled for SSH to provide secure management.

Explanation:
http://www.cisco.com/en/US/tech/tk583/tk617/technologies_tech_note09186a00800949e2.shtml
Generate an RSA key pair for your router, which automatically enables SSH. carter(config)#crypto
key generate rsa
Refer to crypto key generate rsa – Cisco IOS Security Command Reference, Release 12.3 for
more information on the usage of this command.