单项选择题
A．computers B．government agencies C．private companies D．universities
A．Many computers were attacked by a virus in the U. S. B．Many computers attacked by a virus in the U.S. lost their information. C．A computer virus can harm human body. D．A computer virus can help the computer owner do many things.
A．is the same as a biological virus B．is also an organism C．is a series of electronic commands D．is one of biological viruses