Final answer:
d.Broadcast
The type of message received by every system inside the subnet when connected to a hub is a broadcast because hubs send packets to all connected devices without filtering for specific addresses.
Step-by-step explanation:
If every device is connected to a hub and a message is sent out from one device, the type of message received by every system inside the subnet is a broadcast.
A hub is a networking device that operates on the physical layer and forwards every packet it receives to all other ports, regardless of the destination address. Because it sends the packets to each connected device, this would result in a broadcast if one machine sends data to all others on the network. Unlike switches or routers which can direct packets more intelligently, hubs do not filter traffic or distinguish between different types of messages such as unicast (one-to-one), multicast (one-to-many), or broadcast (one-to-all).
Therefore, the correct answer to the student's question is d.Broadcast
The type of message received by every system inside the subnet when connected to a hub is a broadcast because hubs send packets to all connected devices without filtering for specific addresses.