The law of brightness constancy suggests that our perception of an object is a result of the _______ of the light from the object divided by the light surrounding it.

A) sum
B) ratio
C) amount
D) intensity

The law of brightness constancy states that we perceive the color and brightness of an object as constant despite changes in illumination, and this is because our perception of an object is based on the ratio of light emanating from the object to the light present in the surroundings. This allows us to see objects in a consistent manner regardless of their surroundings, which is essential for our ability to navigate the world and recognize objects under varying lighting conditions. Therefore, the best choice is B, ratio.