A、To install a microelectronic wave detector. B、To raise the alarm. C、To install cell phone signal shielding facilities. D、To as

Students sitting the National College Entrance Exam are likely to see cell phone signals blocked inside exam sites this year to prevent cheating.
  While education authorities said they would use modern technology to tighten management of exam sites, the new regulation didn’t bother the majority of local exam takers. The new regulation, which was issued by the Ministry of Education, suggested cities—especially those with a track record of cheating scandals—quip exam sites with cell phone signal shielding facilities. It means handsets won’t work even if students have their phones on during the exam.
  "The city will follow the Ministry of Education’s instruction," said Wang Xin, a publicity official with the Shanghai Education Commission. "But exam site management details have yet to be worked out. Previously, students were only asked to switch off cell phones. However, people could switch their phones to vibration mode."
  In June, 18 students in Guizhou Province were disqualified from the exam after they attempted to Seek help from teachers by sending exam questions via short message. A popular measure that exam organizers take is to install a microelectronic wave detector. An alarm sounds if a cell phone is found working in the classroom. Officials said it is impractical to simply ban handsets from exam rooms as students can hide them in many places or use other devices.