Answer:
Option (C)
Step-by-step explanation:
In a sedimentary sequence of rocks, when the rocks are subjected to stress (pressure) horizontally, then it gives rise to the formation of a series of folds, which are characterized by distinct crests and troughs, which eventually forms long ridges and valleys. These ridges and valleys are oriented in such a way that they are directly perpendicular to the direction of the horizontal stress applied on these rocks.
These folds are very prominent in nature sometimes but most of the time, in an outcrop, they are covered by other rocks and sediments. These folds can be microscopic to macroscopic in scale.
These are some of the most important structures found in the sedimentary rock types.
Thus, the correct answer is option (C).