Final answer:
Gary correctly states that data enters a network through ports and travels via transmission media, although ports are logical rather than physical connection points. Transmission media is the physical infrastructure, such as cables and wireless signals. Gateways facilitate the flow of data, not block it.
Step-by-step explanation:
Gary is partially correct in his statement about the roles of ports and how data travels in a network. However, the explanation requires clarification. Ports in networking are logical access points for different types of services and data transfers; they are part of the software layer of a network, which helps in directing traffic to the correct application or service. So in this sense, data do enter a network through ports. Still, it's important to note that physical ports are where cables connect to devices, which is not what Gary seems to be referring to.
Data indeed travels via transmission media, which can include copper wires, fiber-optic cables, or wireless signals. This is the infrastructure that allows the movement of data from one point to another within a network. Finally, gateways are network points that act as an entry and exit to another network, often interpreting, routing, or performing security functions on the incoming or outgoing traffic, but not blocking it by default as the first option suggests.
Therefore, the most accurate response is potentially Option 3: Gary is right. Packets do travel through transmission media, and data do travel through gateways. This choice accurately describes how data and packets are transmitted and the function of gateways in a network environment.