An American company has started testing a new program aimed at increasing security. Three workers from CityWatcher.com, a company that provides security camera equipment, have volunteered to be electronically monitored. They will have a silicon chip put inside their arms. The tiny device is the size of a grain of rice and will send out radio signals. These will provide information to a central monitoring system that will give the workers access to secure areas of the workplace. The chips were originally designed for medical purposes. Sean Darks, CEO of CityWatcher, said the chips were like identity cards. He said the only difference is that they are inserted inside the person"s body. He added they are very different from Global Positioning Satellite technology, which allows people"s location to be monitored. Mr. Darks insisted that they were not dangerous and even decided to have a chip implanted in his own body. However, many people are worded about the issue of privacy. Many believe the technology could be abused and that new laws will have to be made. Mr. Darks said his workers always choose to have the chips removed.

This passage is mainly about ______.

A．the test of a new security program
B．the increasing security of U.S. companies
C．a new central monitoring system
D．Global Positioning Satellite technology