Answer:
A. The marks in the sand are circular
Step-by-step explanation:
Looking at each one, A makes the most sense. B. The circular marks in the sand are round, you should describe that the marks are in the sand first to describe the setting.
C. The circular marks in the sand are round in shape, the sentence describes that the mark is circular twice, which is unnesscary,
D. The shape of the marks in the sand is circular, circular is not a shape, but a word to describe the roundness of a shape