Which statement regarding the hybrid user authentication model for remote-access IPsec VPNs is correct?

Which statement regarding the hybrid user authentication model for remote-access IPsec VPNs is correct?

A.
VPN servers authenticate by using pre-shared keys, and users authenticate by using usernames and passwords.

B.
VPN servers authenticate by using digital certificates, and users authenticate by using usernames and passwords

C.
VPN servers authenticate by using digital certificates, and users authenticate by using pre- shared keys.

D.
VPN servers and users authenticate by using digital certificates.

E.
VPN servers and users authenticate by using pre-shared keys.