Out of four images which one is the odd one out?

what does the below math rebus puzzle mean?

In the picture, you can see a chess board. On the top left position, the K marks a knight. Now, can you move the knight in a manner that after 63 moves, the knight has been placed at all the squares exactly once excluding the starting square?

Railroad Crossing, look out for the cars. Can you spell that, without any R's ?

What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see? What is it?

I look at you, you look at me I raise my right, you raise your left. What am I?

Why Wine Glass Stem is so long?

Which part of London exists in France as well ?

Transform the word THINK into BRAIN while changing only one letter at a time in a manner that each of the word in the process is a real word!!!

A boy was at a carnival and went to a booth where a man said to the boy, "If I write your exact weight on this piece of paper then you have to give me $50, but if I cannot, I will pay you $50." The boy looked around and saw no scale so he agrees, thinking no matter what the carny writes he'll just say he weighs more or less. In the end the boy ended up paying the man $50. How did the man win the bet?