Robin has been asked to secure network traffic between two application servers. The network administrator is on vacation and is not available to make any changes to the firewall between the servers. There are three applications running between the servers. Currently, Transmission Control Protocol $($TCP$)$ ports $443$ and $1701$ are known to be open, as well as User Datagram Protocol $($UDP$)$ port $500.$ What is the best solution?

Wired Equivalent Privacy $($WEP$)$

VPN using Point$-$to$-$Point Tunneling Protocol $($PPTP$)$

VPN using Layer $2$ Tunneling Protocol $($L$2$TP$)$

Transport Layer Security $($TLS$)$