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.