To determine the lightest tonal value in the photograph, you would typically look for the brightest area. Based on the options provided:
- Light shining through the girl’s hair
- The trees in the background
- The dog’s fur
- The girl’s shadow on the grass
Among these, the "light shining through the girl’s hair" is likely to reflect the lightest tonal value, as light shining through hair usually creates bright highlights. Thus, the correct response would be:
Light shining through the girl’s hair.