Question

There is a temple hidden somewhere high in the mountains in the east. This temple is the home of a strange religion. The believers of this religion have a strange practice. When a new member enters the temple, a red or blue mark is placed on his forehead. If a believer ever finds out that the mark on his own forehead is red, he must leave the temple in the middle of the night never to return. Because there are no mirrors in the mountain, no believer has ever seen the mark on his own forehead. However, they can clearly see the mark on their fellow believers. Since their religion forbids them from talking about the marks of others, nobody has ever left. One day, a traveler comes across the temple and asks "Why do some of you have red marks on your foreheads?" What happens after the traveler leaves? 

Note: In common with many puzzles of this type, the solution relies on the assumption that all participants are totally rational and are intelligent enough to make the appropriate deductions. 

A Nothing. 

B Each day, exactly one believer with a red mark on his forehead leaves the temple. 

C Believers with red marks on their foreheads randomly start leaving. 

D All believers with red marks on their foreheads leave together one day.

Answer 1