How does the parameter “Check for new articles” save bandwidth?

A.
NetCache will query the news server for new articles for all newsgroups individually once per interval

B.
NetCache will query the news serve for new articles for all groups at the same time once per interval

C.
NetCache will not query the server for articles until a request for that newsgroup is made to the cache after the time period has ended

D.
NetCaache will not query the server for new articles until a request for the newsgroup is made to the cache before the time period has ended