Final answer:
Local illumination is the basic level of ray tracing dealing with direct illumination and ambient light, which excludes more complex interactions like light bouncing between objects.
Step-by-step explanation:
When discussing the basic level of ray tracing that is limited to direct illumination and ambient light rays, the correct term is Local illumination. This method considers only the light that travels directly from light sources to objects, and the ambient light present in the scene, without accounting for more complex interactions like reflections off of other objects. Local illumination models are simpler and less computationally intensive than Global illumination models, which simulate the indirect effects of light bouncing around a scene.