Based on the image shown, we know that the mounting technique used by Sarah is the D. photo corners.
Photo Corners mounting technique
- Allows for one to be able to hang portraits in a frame.
- Involves using shapes at the corners of the frame to hold the picture intact.
The frame shown in the picture has shapes at its corners to better hold the picture so we can say that this is a photo corner mounting technique being used.
In conclusion, option D is correct.
Find out more on mounting techniques at https://brainly.com/question/8875683.