Class B has the greatest number of hosts per given network address.

Explanation:

To understand why Class B has the greatest number of hosts per given network address, let's first understand the concept of network classes.

In the early days of the Internet, IP addresses were divided into five different classes: A, B, C, D, and E. Each class had a different range of possible network addresses and host addresses.

- Class A: Class A IP addresses have a range from 0.0.0.0 to 127.255.255.255. The first bit of the address is always 0. Class A networks are used for large organizations as they provide a large number of network addresses but a relatively small number of hosts per network.

- Class B: Class B IP addresses have a range from 128.0.0.0 to 191.255.255.255. The first two bits of the address are always 10. Class B networks are used for medium-sized organizations as they provide a smaller number of network addresses compared to Class A but a larger number of hosts per network.

- Class C: Class C IP addresses have a range from 192.0.0.0 to 223.255.255.255. The first three bits of the address are always 110. Class C networks are used for small organizations or home networks as they provide a larger number of network addresses but a smaller number of hosts per network.

Now, let's compare the number of hosts per network address for each class:

- Class A: Class A networks have 8 bits reserved for the network address, leaving 24 bits for the host address. This gives a total of 2^24 (16,777,216) possible hosts per network.

- Class B: Class B networks have 16 bits reserved for the network address, leaving 16 bits for the host address. This gives a total of 2^16 (65,536) possible hosts per network.

- Class C: Class C networks have 24 bits reserved for the network address, leaving only 8 bits for the host address. This gives a total of 2^8 (256) possible hosts per network.

From the above comparison, it is clear that Class B has the greatest number of hosts per given network address. It provides 65,536 possible hosts per network, which is significantly larger than the 256 hosts provided by Class C and the 16,777,216 hosts provided by Class A.

Therefore, the correct answer is option 'B'.