The correct answer is C. Duplex.
Duplex is a connection between two end points, either physical or logical, over which data may travel in both directions simultaneously. There are two types of duplex: full duplex and half duplex.
Full duplex is a connection in which data can be transmitted in both directions at the same time. This is the most common type of duplex.
Half duplex is a connection in which data can only be transmitted in one direction at a time. This is less common than full duplex, but it is sometimes used in situations where there is a lot of interference on the line.
A dump point is a location where data is transferred from one system to another. This is usually done for the purpose of backup or archiving.
A datalink is a layer of communication between two devices. It is responsible for error detection and correction, as well as flow control.
A network is a group of computers that are connected together so that they can share information and resources.
E is not the correct answer because it is not a type of duplex.