Which description of the setting signals the climax of the story

A. "Druse withdrew his eyes from the valley and fixed them again upon group of man and horse in the sky, and again it was through the sights of his rifle."

B. "At a distance of a quarter-mile before him, but apparently at a stones's throw, rose from its fringe of pines the gigantic face of rock, towering to so great a height above him that it made him giddy to look up to where its edge cut a sharp, rugged line against the sky."

C. " At some distance away to his right it presented a clean, vertical profile against a background of blue sky to a point half the way down, and of distance hills, hardly less blue, thence to the tops of the trees at its base."

D. "Lifting his eyes to the dizzy altitude of its summit the officer saw astonishing sight-a man on horseback riding down into the valley  through the air!''

The answer would be d, coherence.