Which best describes imei?
a hardware piece that controls network connectivity
a unique identifier for a mobile phone
a unique identifier for a wireless subscriber
a unique identifier on a sim card

In the given question first, second, and the fourth line is correct.   Explanation:

To identify any device on a network the IMEI number is used, It is a 15 digit number, which defines the uniqueness of your devices. It is also known as a social security number. It is not used for Wi-Fi users, and the other three options were correct, which can be described as follows:

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