Answer:
C is correct, D might be correct if you forgot 000 at the end of the question.
Explanation:
005 = 5x1 so A is incorrect
945 = 9x100 + 4x10 + 5x1 so B is incorrect
15.859 = 1x10 + 5x1 + 8/10 + 5/100 + 9/1000 + so C is correct
973.001 = 9x100 + 7x10 + 2x1 + 1/1000 so D is incorrect