Answer:
The correct answer is - option C. Law of superposition.
Step-by-step explanation:
According to the law of superposition states that within a sequence of layers of natural sedimentary rock without any disturbance, the oldest layer is lies under the younger layers with ascending order in the sequence.
If a sedimentary rock has 4 layers as a, b, c and d where the younger layer d would be on top and the oldest layer a would be at the bottoms.
Thus, the correct answer is - option C.