Andy, Brian, Celline, and Drake were captivated by a very bad person, and were positioned as what can be seen in the picture below. All of them face a wall. Each of them was given a hat. No one of the four knows the colour of the hat that is wore by themselves, but they know that there are 2 red and 2 blue coloured hats.
The bad person told them that one of them have to name the colour of the hat him/herself wear. There’s only one chance. If the answer is wrong, all of them will be killed.
To save all of them who needs to give the answer and why?
(better not open this if you don’t have any answers yet)