Final answer:
The three valid public addresses are 198.133.219.17, 128.107.12.117, and 64.104.78.227.
Step-by-step explanation:
The three valid public addresses out of the given options are:
- 198.133.219.17
- 128.107.12.117
- 64.104.78.227
Public addresses are IP addresses that can be used on the internet. Private addresses, such as 192.168.1.245 and 10.15.250.5, are reserved for use within private networks and are not reachable directly from the internet.