When most people stare first at a blue circle and then shift their eyes to a white surface,the afterimage of the circle appears

A) yellow.
B) red.
C) green.
D) blue.

When people stare at a blue object and then look away at a white surface, the afterimage appears yellow. This is due to the opponent-process theory of color vision, which suggests that colors are perceived in opposing pairs: blue-yellow, red-green, and black-white. Staring at blue fatigues the blue receptors, making the opposing color, yellow, more prominent in the afterimage.