The correct option is A ruffled
The word 'serene' refers to something calm peaceful and untroubled.
Option A, scenic refers to a pleasing and attractive natural scenery.
Option B, clear refers to something easy to perceive, understand or interpret.
Option C, tranquil refers to something free from disturbance or calm.
Option D, ruffled refers to disturbing the smoothness or tranquillity of something.
Thus, according to the meaning, the word 'ruffled' is the opposite of the word 'serene'.