Correct Answer - Option 3 : (ii) and (iv) only
Concept:
Stateless protocols: A stateless protocol does not require the server to retain session information or status about each communicating partner for the duration of multiple requests. Each request is treated as an independent transaction.
Stateful protocols: A protocol that requires keeping of the internal state on the server is known as stateful protocol.
Explanation:
HTTP: Hypertext transfer protocol is a stateless protocol. No information is maintained by server in this protocol.
FTP: File transfer protocol is a stateful protocol. It remembers all the log files corresponding to the client.
TCP: Transfer control protocol is not an application layer protocol. TCP works at transport layer.
POP3: It is a client/ server protocol in which e-mail is received and held by the internet server. It is a stateful application layer protocol.
Therefore, option 3 is correct