The correct answer is C. under.
The word “under” is used to indicate a position below or beneath something else. In this case, the tree is providing shade, so the area under the tree is shady.
The word “below” can also be used to indicate a position lower than something else, but it does not necessarily mean that the thing below is hidden or covered. For example, you might say that your house is located below the mountain, but this does not mean that your house is hidden by the mountain.
The word “beneath” is similar to “below,” but it is more formal and literary. It is often used to describe something that is hidden or covered. For example, you might say that the treasure was buried beneath the ground.
The word “none of three” is not the correct answer because the word “under” is the only word that accurately describes the position of the shady area.