What function does pressing the Tab key have when entering a command in IOS?

What function does pressing the Tab key have when entering a command in IOS?

• It aborts the current command and returns to configuration mode.
  

• It exits configuration mode and returns to user EXEC mode.
  

• It moves the cursor to the beginning of the next line.
  

• It completes the remainder of a partially typed word in a command.
  

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Explanation: Pressing the Tab key after a command has been partially typed will cause the IOS to complete the rest of the command.