A technician is trying to retrieve a screw that fell inside a case and is just out of reach. Which of the following is the BEST procedure to retrieve the screw?（）

• A、Turn the case upside down, shake gently and let the screw fall out.
• B、Use a shop vacuum to retrieve the screw.
• C、Use the hardware abstraction layer (HAL).
• D、Use an extension magnet.