CompTIA A+ 220-901

Answer: B - 255.255.0.0 is the default subnet mask for the Class B IP Address 133.142.7.82.

Key Takeaway - An IP address that begins with 133 can be automatically classified as a Class B IPv4 Address; class B IP addresses have the default Subnet Mask 255.255.0.0, which designates the first two octets (133.142) as the Network address, and the last two octets (7.82) as the node address. Class A addresses range from 1-126, Class C from 128-191, and Class D from 192.223.