3 people(a,b,c) r standing in a row facing in the same direction so that b can see only a and c can see both a and b. a,b and c are wearing hats of colous either white,black and white or black ,white and black( 2 colour combination) respectively but they dont know which colour hat they are wearing(obviously they r able to see the hat colour of the person in front of them).So which person/s will tell the hat of his colour 1st?