You ask your ISP to assign a public IP address for the external interface of your Windows 2000 server, which is running a proxy server application. In the email message you get that contains the information, the ISP tells you that you have been assigned the IP address 203.15.226.12/24. When you fill out the subnet mask field on the IP configuration dialog box on your system, what subnet mask should you use?
A. 255.255 .255 .255
B. 255.255 .255 .0
C. 255.255 .240 .0
D. 255.255 .255 .240