He was the most eccentric and difficult patron.

Answer: Option A

Eccentric : (of a person or their behaviour) unconventional and slightly strange.
Normal : conforming to a standard; usual, typical, or expected.
Sober : not affected by alcohol; not drunk.
Genial : friendly and cheerful.
Sociable : willing to talk and engage in activities with other people; friendly.

Antonym of Eccentric is Normal