There is a land where every inhabitant is either a day-knight or a night-knight. Day-knights tell the truth in the day and lie at night. Night-knights lie in the day and tell the truth at night.
Members of the Smith family are day-knights and, members of the Jones family are night-knights.
Four inhabitants Art, Barry, Cole and Dan approach a visitor to the island. It is known that precisely two of them are members of the Jones family and the remaining two are members of the Smith family.
Art: Barry’s last name is Smith.
Barry: Cole belongs to the Jones family.
Cole: Art and Dan are from different families.
Dan: Art and Barry are from the same family.
What are the surnames of the three inhabitants? Is it day or night?