According to stratigraphy and its laws, what is the correct order – from oldest to youngest – of the following rock strata:

b, c, a, d
d, c, b, a
b, c, d, a
a, b, c, d

option (4)

Explanation:

According to the stratigraphic law of superposition, the layers of rocks that are at the base are the oldest rocks and those that are at the top are considered to be the youngest rock. This law enables the geologists to determine the age of the rock beds.

Considering the rock layer that is deposited at the bottom be A, followed by the next rock sequences B, C and D respectively, it can be concluded that rock layer A that is present at the bottom is the oldest rock and the rock layer D that is at the apex is the youngest rock.

Thus, the correct order from oldest to the youngest rock is A, B, C and D.

Hence, the correct answer is option (4).