The correct answer is B. Duplex.

Duplex printing is the process of printing on both sides of a sheet of paper automatically or manually. Duplex printing can save paper, reduce clutter, and create professional-looking documents. To print on both sides of the paper, the printer must support duplex printing or the user must manually reinsert the pages to print the second side.

Orientation is the direction in which the paper is printed, either portrait (vertical) or landscape (horizontal). Orientation does not affect the ability to print on both sides of the paper.

Quality is the resolution or sharpness of the printed image, measured in dots per inch (dpi). Quality does not affect the ability to print on both sides of the paper.

Print tray is the part of the printer that holds and feeds the paper into the printer. Print tray does not affect the ability to print on both sides of the paper.

To enable duplex printing on a Windows PC, follow these steps1:

Open the document for printing, then select File > Print.

In Settings, select Manually Print on Both Sides, then Print.

Follow the instructions on the screen to flip and reinsert the pages.

To enable duplex printing on a Mac, follow these steps2:

Open the document for printing, then select File > Print.

In Layout, select Two-Sided, then Long-Edge binding or Short-Edge binding.

Click Print.