What is the default subnet mask for Class B private IPv4 addresses?

The default subnet mask for Class B private IPv4 addresses is 255.255.0.0. Class B addresses range from 128.0.0.0 to 191.255.255.255, and the private Class B address space specifically includes the range from 172.16.0.0 to 172.31.255.255. A subnet mask of 255.255.0.0 indicates that the first two octets (the first 16 bits) are reserved for the network part of the address, allowing for a large number of hosts within that network. This configuration is ideal for medium to large-sized networks, providing significant flexibility in addressing hosts compared to smaller subnet masks.

The other options do not represent the default subnet mask for Class B private addresses. For example, 255.0.0.0 is a default subnet mask for Class A, while 255.255.255.0 is typical for Class C addressing. The option labeled N/A does not apply since there is a specific default subnet mask for Class B private IPs. Thus, the answer correctly identifies the appropriate default subnet mask associated with Class B private IPv4 addresses.