Correct : P

Given:
Protocols to check: (i) HTTP, (ii) FTP, (iii) TCP, (iv) POP3.
Condition: Stateful protocol at the application layer.
To find:
Which of the given protocols are stateful application layer protocols.
Solution:
Let me check each protocol one by one for two things: layer of operation and whether it is stateful.
First, check (i) HTTP:
HTTP works at the application layer, but by default it is stateless because the server does not retain any information about previous client requests.
So, HTTP is not stateful.
Next, check (ii) FTP:
FTP operates at the application layer and maintains state information (like current directory and user login state) throughout the control connection session.
So, FTP is a stateful application layer protocol.
Next, check (iii) TCP:
TCP is indeed stateful (maintains connection state, sequence numbers, etc.), but it operates at the transport layer, not the application layer.
So, TCP is ruled out.
Finally, check (iv) POP3:
POP3 works at the application layer and maintains state across the session (like authorization, transaction, and update states to keep track of emails marked for deletion).
So, POP3 is also a stateful application layer protocol.
Combining the valid ones, we have (ii) and (iv).
Answer:
(C) (ii) and (iv) only