Which of the following are transport layer protocols?a.TCP and UDPb.ATMc.CISCd.HTTP and FTP

The transport layer protocols from the options provided are TCP and UDP. So, the answer is a. TCP and UDP.

Here's a brief explanation:

a. TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) are both transport layer protocols. They are responsible for the delivery of a message from one process to another.

b. ATM (Asynchronous Transfer Mode) is not a transport layer protocol. It is a network protocol that transmits data at a very high speed in the form of small fixed-size cells.

c. CISC (Complex Instruction Set Computing) is not a protocol at all. It is a type of design for the computer's central processing unit (CPU).

d. HTTP (Hypertext Transfer Protocol) and FTP (File Transfer Protocol) are not transport layer protocols. They are application layer protocols used for data transfer over a network.