A、130. B、3,900. C、13,000. D、1,300. D短文第二段明确提到On average，each email user received 1,300 spam messages last year。

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    Junk email messages like these, also known as spam, are familiar to anyone with an email account. On average, each email user received 1,300 spam messages last year, and that number is expected to increase to 3,900 by the year 2007.
    Junk mail is nothing new. For years, marketing groups have collected consumer information, including addresses and phone numbers, and sold them as lists to interested advertisers. But with junk mail, the high cost of mailing packages to large groups of people kept it down to a manageable level. But with email, anyone With a computer and Internet connection can now send messages around the world for free.
    But it’s the people who receive spam who wind up paying. It is estimated that spam costs companies millions of dollars every year due to wasted time, connection costs and lost emails.