Which of the following keys is pressed to enter the Windows boot options after POST?（）

A networking device that sends packets to all connections is a:（）

A. gateway.
B. hub.
C. switch.
D. router.

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A technician is servicing a customer’s color laser printer and notices excess toner in the printer.Which of the following tools would BEST assist the technician in removing the excess toner?（）

A. Damp towel
B. Compressed air
C. Alcohol wipe
D. Computer vacuum

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