[Tutorial] Creating a duotone effect

[Andrius]

The duotone effect is a very striking and colorful effect inspired by a popular printmaking technique. The effect is achieved by recreating an image using just two colors — one for the dark parts of the image and one for the light ones. This usually emphasizes the midtones and highlights, drawing attention to the subjects in a photo. And the best part? Creating this effect couldn’t be simpler.
Read the full tutorial.

[auludag]

At the end it says "Simply choose the Color Adjustments tool and apply the Black & White adjustment to the same image."

There is no such Black & White selection in that.