A local library branch just dealt with a major computer virus that almost shut down the network. If you were the library's IT technician, what is the best advice you could give them to prevent this from happening again?

A. Install a firewall, and set standards for network use.
B. Throw away all infected hardware, and buy new hardware.
C. Don't allow the public to use the library computers.
D. Only allow customers to use government websites.