The diagram below shows a stack of rock layers. These layers have not changed position since they formed. Examine the diagram and answer the question that follows. If the age of Layer 4 is 400 million years and the age of Layer 1 is 500 million years, then the age of Layer 3 is A. older than 500 million years. B. between 400 million and 500 million years. C. 500 million years. D. younger than 400 million years.