The diagram shows the fossils found in different layers of a rock. (3 points) A diagram labeled Fossil Layers is shown. The topmost layer is labeled A and shows the skeleton of a fish, the second layer from the top is labeled B and shows a shell, the third layer from the top is labeled C and shows a fern leaf, and the lowermost layer shows an oak leaf
In which layer is the oldest fossil found?
Layer A
Layer B
Layer C
Layer D