Riddle 1: C will call out. D can see the two in front. If in front 2 is same color, then D will know his color. Since D keep quiet, then C will know that his color is different from B.
Riddle 2: Ask the bird: If I am going to ask the other bird which door leads to hell, what will it says? Then I will choose the door said by the bird because it is the door that will lead to the HEAVEN.
a stamp.. 'whats long and hard.. babys have it short.. guys have it long.. and gets hairy as they grow older?'