The correct answer is: A. Synchronous
Synchronous transmission is a type of data transmission in which data is transmitted in blocks, with a fixed time interval between each block. This allows the receiver to synchronize its clock with the sender’s clock, which is necessary for accurate data reception.
Asynchronous transmission is a type of data transmission in which data is transmitted one character at a time, without any fixed time interval between characters. This makes asynchronous transmission less efficient than synchronous transmission, but it is simpler to implement and can be used over slower connections.
Timed interval is a type of data transmission in which data is transmitted in blocks, with a fixed time interval between each block. However, unlike synchronous transmission, the receiver does not need to synchronize its clock with the sender’s clock. This makes timed interval transmission less efficient than synchronous transmission, but it is simpler to implement and can be used over slower connections.
PPP is a Point-to-Point Protocol, which is a standard protocol for establishing a direct connection between two computers. PPP is not a type of data transmission, but it can be used to transmit data in either synchronous or asynchronous mode.
Therefore, the correct answer is A. Synchronous.