The word "it" in paragraph 3 refers to __________

Câu hỏi: Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 39 to 45.
Sensing phantom phone vibrations is a strangely common experience. Around 80% of us have imagined a phone vibrating in our pockets when it's actually completely still. Almost 30% of us have also heard non-existent ringing. Are these hallucinations ominous signs of impending madness caused by digital culture?
In fact, phantom vibrations and ringing illustrate a fundamental principle in psychology. It's an example of a perceptual system, just like a fire alarm, an automatic door, or a daffodil bulb that must decide when spring has truly started. Your brain has to make a perceptual judgment about whether the phone in your pocket is really vibrating. And, analogous to a daffodil bulb on a warm February morning, it has to decide whether the incoming signals from the skin near your pocket Indicate a true change in the world.
Psychologists use a concept called Signal Detection Theory to guide their thinking about the problem of perceptual judgments. Analyzing the example of phone vibrations, we can see how this theory explains why they are a common and unavoidable part of healthy mental function. When your phone is in your pocket, the world is in one of two possible states: the phone is either ringing or not. You also have two possible states of mind: the judgment that the phone is ringing, or the judgment that it isn't. Obviously, you'd like to match these states in the correct way. True vibrations should go with "it's ringing", and no vibrations should go with "it's not ringing". Signal detection theory calls these faithful matches a "hit" and a "correct rejection", respectively.
But there are two other possible combinations: you could mismatch true vibrations with "it's not ringing" (a "miss"); or mismatch the absence of vibrations with "it's ringing" (a "false alarm"). This second kind of mismatch is what's going on when you imagine a phantom phone vibration.
For situations where easy judgments can be made, such as deciding if someone says your name in a quiet room, you will probably make perfect matches every time. But when judgments are more difficult - if you have to decide whether someone says your name in a noisy room, or have to evaluate something you're not skilled at - mismatches will occasionally happen. And these mistakes will be either misses or false alarms.
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https://www.bbc.com/future/artide/20130701-why-you-feel-phantom-phone-calls

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The word "it" in paragraph 3 refers to __________
A. judgement verte
B. Mind
C. state
D. phone