The correct answer is D. Preferrable. The correct spelling is "preferable".
A. Predilection is a noun that means a strong liking or preference for something. B. Discipline is a noun that means a system of rules that are enforced in order to train people to behave in a particular way. C. Indigenous is an adjective that means native to a particular place.
The word "preferrable" is not a word in the English language. The correct spelling is "preferable".
