____________ is a client or database-generated identifier that uniquely identifies this message.
(a) messageLength
(b) responseTo
(c) requestID
(d) all of the mentioned
(a) messageLength
(b) responseTo
(c) requestID
(d) all of the mentioned
Right choice is (c) requestID
Explanation: For the case of client-generated messages, it will be returned in the responseTo field of the OP_REPLY message.