A company has decided to allow certain users to work remotely by opening up a VPN connection through the firewall. The security policy has been updated to allow VPN connections only from certain users and to specific areas on the network. Along with configuring the correct policies on the firewall, which of the following also needs to be configured on users` mobile devices to allow these VPN connections? 

Answer options:

A. VNC application
B. Kerberos
C. Geotagging application
D. Credentials

D