Answer:
is horizontal.
Explanation:
The monocline folds are those folds that consists of two horizontal limbs. It happens in one-simple step by a bend in the rock layers. It is also known as monoform.
In this geological fold, the oldest rocks are at the bottom and youngest rocks at the top.
Some examples of monocline folds are Waterpocket Fold in Utah, Lapstone monocline in Australia.
Therefore, horizontal is the correct answer.