正解:B
Explanation
Shoulder surfing is a threat that involves someone looking over another person's shoulder to observe their screen, keyboard, or other sensitive information. Shoulder surfing can be used to steal passwords, personal identification numbers (PINs), credit card numbers, or other confidential data. The use of a privacy screen on a computer can help prevent shoulder surfing by limiting the viewing angle of the screen and making it harder for someone to see the screen from the side or behind. Impersonation, whaling, and tailgating are not threats that can be prevented by using a privacy screen on a computer.