The correct answer is A. simulator.
A simulator is a computer-controlled device that duplicates the work environment for training exercises. It is used to train people on how to operate equipment or perform tasks in a safe and controlled environment. Simulators are often used in industries such as aviation, healthcare, and manufacturing.
A duplicator is a machine that makes copies of documents or other materials. It is not used for training exercises.
A trainer is a person who teaches or trains others. It is not a computer-controlled device.
A COM device is a communication device that connects computers to other devices. It is not used for training exercises.
None of the above options are correct. The correct answer is A. simulator.