Which of the following is a Class C IP address?

A Class C IP address is characterized by its range, which is from 192.0.0.0 to 223.255.255.255. In the given options, the IP address 192.168.40.15 falls within this range, making it a valid Class C address. Class C addresses are commonly used for smaller networks and typically support up to 254 hosts, which is beneficial for home and small business networks that require a subnetted layout.

Considering the other options, 10.0.0.1 is a Class A address falling within the range of 10.0.0.0 to 10.255.255.255. The IP address 172.16.0.0 belongs to Class B, which ranges from 128.0.0.0 to 191.255.255.255. Lastly, 127.0.0.1 is a special loopback address used for testing, which also does not classify as a Class C address. Therefore, 192.168.40.15 is the recognized Class C IP address among the options provided.