Which of the following types of transmission is the process of sending one bit at a time over a
single transmission line?

A.
Unicast transmission

B.
Serial data transmission

C.
Multicast transmission

D.
Parallel data transmission

Explanation:

In serial data transmission, one bit is sent after another (bit-serial) on a single transmission line. It
is the simplest method of transmitting digital information from one point to another. This
transmission is suitable for providing communication between two participants as well as for
multiple participants. It is used for all long-haul communication and provides high data rates. It is
also inexpensive and beneficial in transferring data over long distances.

Answer option D is incorrect. In parallel data transmission, several data signals are sent
simultaneously over several parallel channels. Parallel data transmission is faster than serial data
transmission. It is used primarily for transferring data between devices at the same site. For
instance, communication between a computer and printer is most often parallel, allowing the entire
byte to be transferred in one operation.
Answer option A is incorrect. The unicast transmission method is used to establish communication
between a single host and a single receiver. Packets sent to a unicast address are delivered to the
interface recognized by that IP address, as shown in the following figure:

Answer option C is incorrect. The multicast transmission method is used to establish
communication between a single host and multiple receivers. Packets are sent to all interfaces
recognized by that IP address, as shown in the figure below: