A lie detector apparatus is also known as a:

Correct option is A

The correct answer is option (A) Polygraph

• A polygraph is a lie detector apparatus that measures and records several physiological indicators, such as heart rate, blood pressure, respiratory rate, and skin conductivity, while a person is being questioned.
• The theory behind the polygraph is that deceptive answers will produce physiological responses that are distinct from those associated with truthful answers.
  

Information Booster :-

• A seismograph is an instrument used to detect and record the motion of the Earth's surface.
  
• A barograph is a type of barometer that records atmospheric pressure over time. It is typically used in meteorology.
  
• A polarimeter is an instrument used to measure the optical rotation of substances, typically used in chemistry to analyze substances like sugars.