How many host addresses are available with a Class B network with the default mask?

63,998 is an incorrect calculation for the number of available hosts in a Class B network.

64,QQQ is not a valid numerical answer and is an incorrect calculation.

A Class B network uses a default subnet mask of 255.255.0.0, dedicating the last two octets (16 bits) to the host portion. This provides 2^16 = 65,536 total possible host addresses. However, two addresses are reserved: one for the network address (all host bits set to 0) and one for the broadcast address (all host bits set to 1). Subtracting these two leaves 65,534 usable host addresses.

65,536 represents the total possible combinations for 16 host bits, but it does not account for the two reserved addresses (network and broadcast) which are not usable for hosts.