根据以下材料，回答题。Electronic MailDuring the past few years，scientists all over the world

根据以下材料，回答题。

Electronic Mail

During the past few years，scientists all over the world have suddenly found themselves productively engaged in task they once spent their lives hvoiding——writing，any kind of writing，but particularly letter writing.Encouraged by electronic mail’s surprisingly high speed，convenience and economy，people who never before touched the stuff are regularly，skillfully，even cheerfullv tapping out a great deal of correspondence.

Electronic networks，woven into the fabric of scientific communication these davs. are the route to colleagues in distant countries，shared data，bulletin boards and electronic Joumals.Anyone with a personal computer， a modern and the software to link computers over teleDhone lines can sign on？An estimated five million scientists have done SO with more joining every day，most of them communicating through a bundle of interconnected domestic and foreign routes known collectively as the Internet，or net.

E-mail is starting to edge out the fax，the telephone，overnight mail，and of course.1and mail. It shrinks time and distance between scientific collaborators，in part because it is conveniently asynchronous（异步的）（Writers can type while their colleagues acmss time zones sleep;their message will be waiting.）.If it is not yet speeding discoveries，it is certainly accelerating communication.

Jeremy Bernstein，the physicist and science writer，once called E-mail the Dhysicist，s umbilical cord（脐带）.Later other people，t00，have been discovering its connective virtues.Physicists are using it;college students are using it;everybody is using it;and as a sign that it has come of age，the New Yorker has celebrated its liberating presence with a cartoon—an appreciative dog seated at a keyboard，saying happily，“on the Internet，nobody knows you’re a dog.”

The reasons given below about the popularity of E—mail can be found in the passage except 查看材料

A.direct and reliable

B.time—saving in delivery

C.money-saving

D.available at any time