Melissa and LoveLetter made use of the trust that exists between friends or colleagues.Imagine receiving an （） from a friend who asks you to open it. This is what happens with Melissa and several other similar email （） . Upon running, such worms usually proceed to send themselves out to email addresses from the victim’s address book, previous emails, web pages （） . As administrators seek to block dangerous email attachments through the recognition of well-known （） , virus writers use other extensions to circumvent such protection.Executable (.exe) files are renamed to .bat and .cmd plus a whole list of other extensions and will still run and successfully infect target users. Frequently, hackers try to penetrate networks by sending an attachment that looks like a flash movie, which, while displaying some cute animation, simultaneously runs commands in the background to steal your passwords and give the （） access to your network.

As administrators seek to block dangerous email attachments through the recognition of well-known （）.

A．names

B．cookies

C．software

D．extensions

某中药饮片生产企业于2010年11月取得《药品生产许可证》。

该中药饮片生产企业的《药品生产许可证》下列哪项发生变更，应当在原许可事项发生变更30日前，向原发证机关提出变更申请（）

A.法定代表人

B.企业名称

C.注册地址

D.生产地址