While attempting to overcome writer’s block, devin stares at her yellow, green, and white striped journal. when she finally returns to her blank computer screen, she sees a blue, red, and black striped afterimage. which theory best explains the afterimage that devin sees?

Opponent process theory Devin is seeing a "negative afterimage" which is generally caused by the rods and cones in the eye adapting to over stimulation and losing sensitivity. The opponent process theory by Ewald Hering explains this phenomena by claiming that the eye sees three channelsl red versus green, blue versus yellow, and black versus white. When the green channel is over stimulated, then it starts to return a weaker green signal, which is then interpreted as magenta. The same applies to the other channels.

True. you know, tools like shovels.