According to the text, what is the major cause of the flooding spam?A.Companies rely on

Accordingtothetext,whatisthemajorcauseofthefloodingspam?

A.Companiesrelyone-mailforcommunications.

B.Morepeopleintheworldcommunicatebye-mail.

C.Manycomputervirusescontainspame-mail.

D.Moreadvertisersbegintopromotesalesthroughspam.

推理判断题。由第二自然段中的Asmoreandmoreadvertisersturntospamtoselltheirproducts,individuale-mailboxesareoftenfloodedwithspame-mails.一句可知本题选D。