What is the classful netmask assigned to Emily's laptop, which uses IP address 192.10.10.10 at work?

The classful netmask assigned to an IP address is determined by the class of the IP address. The IP address 192.10.10.10 falls within the range of Class C addresses, which spans from 192.0.0.0 to 223.255.255.255. Class C addresses use a default subnet mask of 255.255.255.0.

This netmask allows for 256 addresses in the subnet (0-255), with the last octet reserved for host addresses, making it suitable for smaller networks. In a Class C network, the first three octets (192.10.10) represent the network portion, while the last octet (0-255) represents individual devices on that network.

The other options represent netmasks for different classes of IP addresses. Option B, 255.255.0.0, is the default mask for Class B addresses, which are used for larger networks. Option C, 255.0.0.0, corresponds to Class A addresses, which can accommodate an even larger number of hosts. Option D, 255.255.255.255, is a special address typically used for broadcast purposes and does not represent a valid