A very special island is inhabited only by knights and knaves. Knights always tell the truth, and knaves always lie. You meet 6 inhabitants: Isabella, Jackson, Mason, Harper, Avery, and Sofia. Isabella remarked, "Sofia is a knave if and only if Mason is a knave". Jackson was heard saying, "Mason is a knave if and only if Harper is a knave". According to Mason, "Sofia is a knight or Jackson is a knight". Harper told you that Avery is a knight. "Isabella is a knight and Jackson is a knight," Avery declared. "Avery is not a knave" - Sofia. So who is a knight and who is a knave?
Isabella is a knight, Jackson is a knight, Mason is a knight, Harper is a knight, Avery is a knight, and Sofia is a knight.
(1) Isabella is a knight
(2) Jackson is a knight
(3) Mason is a knight
(4) Harper is a knight
(5) Avery is a knight
(6) Sofia is a knight
Assume Isabella is a knight. No contradiction is found in their claim that Sofia is a knave if and only if Mason is a knave. Assume Sofia is a knight. No contradiction is found in their claim that Avery is not a knave. Assume Avery is a knight. No contradiction is found in their claim that Isabella is a knight and Jackson is a knight. Assume Jackson is a knight. No contradiction is found in their claim that Mason is a knave if and only if Harper is a knave. Assume Mason is a knight. No contradiction is found in their claim that Sofia is a knight or Jackson is a knight. Assume Harper is a knight. No contradiction is found in their claim that Avery is a knight.