Caleb has just installed an open$-$source application on a web server to host a wiki for the customer service department. Which of the following should he do to harden the application after installation?

a$.$ Block port $443$ on the firewall in front of the web server.

b$.$ Configure SNMPv$1$ on the server to help with automation and management.

c$.$ Disable SSH and enable telnet on the server for remote administration.

d$.$ Change the default password.