A is the correct answer.
Explanation:
Watermarks are faint logos which are superimposed over the photo. It is used to prevent others from copying and using your photos without permission. Websites use it for showing that image is copyrighted and can't be used without permission. Watermarking the images is an easy process. One can use software like Adobe Photoshop, Microsoft paint 3D and others for watermarking the images. Apps can also be used. Always create copies of your images and use the copies instead of the original images.
physiological variable spikr during the telling of a lie
the other three are examples of why it may not be completely accurate