CAYLEY 2007 Problem 17

On an island there are two types of inhabitants: Heroes who always tell the truth and Villains who always lie. Four inhabitants are seated around a table. When each is asked “Are you a Hero or a Villain?”, all four reply “Hero”. When asked “Is the person on your right a Hero or a Villain?”, all four reply “Villain”. How many Heroes are present?

Answer Choices
A. 0
B. 1
C. 2
D. 3
E. 4