Which statement about the HTTP protocol is true?

Which statement about the HTTP protocol is true?

A.
The request method does not include the protocol version.

B.
The proxy acts as an intermediary receiving agent in the request-response chain.

C.
The tunnel acts as an intermediary relay agent in the request-response chain.

D.
The gateway acts as an intermediary forwarding agent in the request-response chain.

E.
The success and error codes are returned in the response message by the user-agent.