Where does the name ‘Grand Staircase’ come from?

Where does the name ‘Grand Staircase’ come from?

A Unique geological feature
B A series of stepping stones
C Architecture made by park rangers

The term ‘Grand Staircase’ refers to the sequence of vivid cliffs and plateaus that cascade like nature’s very own staircase in the Colorado Plateau. These layers are crafted from an assortment of sedimentary rock types, chiselled and sculpted by the patient hand of time over millennia.

The correct answer is Unique geological feature.