TheHypertextTransferProtocol,theWeb's()protocol,isattheheartoftheWeb.HTTPisimplementedintwoprograms:a()programandaserverprogram.Theclientprogramandserverprogramexecutingondifferentendsystems,talktoeachotherby(请作答此空)HTTPmessages.HTTPdefineshowWebclientsrequestWebpagesfromserversandhowserverstransferwebpagestoclients.whenauser()awebpage,thebrowsersendshttprequestmessagesfortheobjectsinthepagetotheserver.Theserver()therequestsandrespondswithhttpresponsemessagesthatcontaintheobjects.
A.exchanging B.changing C.declining D.removing正确答案A