According to the passage, which of the following is true？A．Scientists have found a way to

According to the passage, which of the following is true？

A．Scientists have found a way to get rid of the viruses.

B．The Jerusalem Viruses are a great harm to human's health.

C．The viruses will come to a new computer after staying in the old one for some time.

D．Last year four countries found out their computers were infected by viruses.