Color illusion

Some people think everything's dark. Some people think everything's clear. Some believe that everything is black or white, and some think that there are infinite shades of gray.

In any case, one thing is what we see and other one is that what we think we seer.

Let's look at this example, and try to figure out which box is clearer, A or B.

To see the solution, let's have a look at:

Color illusion