Choose your answer?

A hillside along a highway has exposed layers of undisturbed sedimentary rock. Which method would be best for scientists to use to determine the relative age of these sedimentary rock layers?

Available options:
(i) apply the law of superposition.
(ii) calculate the rate of radiometric decay.
(iii) apply the law of crosscutting relationships.
(iv) calculate the rate of tectonic plate movement.
(i)