What is a requirement to enable Cisco IOS IPS with 5.x signature？（）
- Adisable Zone-Based Firewall as the two features are not compatible
- Bdisable Cisco Express Forwarding as the two features are not compatible
- Cgenerate a certificate and export on Cisco.com to receive a signature update
- Dimport the public RSA key from the Cisco IPS team that allows the router to verify that a signatureupdate （which was signed by this key） comes from Cisco