please help answer this..and explain why!
Question: Which one of the following choices is NOT a way to successfully connect an Outlook 2003 client to an Exchange 2003 server protected by firwall that allows port 25, 80, and 443 access to the server?
a. RPC connection by Exchange server name using a VPN on a local LAN
b. Offline with RAS dialup access to the business network for updates
c. RPC Connection to the server's public IP address
d. RPC Connection by Exchange servername using a VPN across the Internet\
e. RPC over HTTPS across the public Internet