Final answer:
Transduction is the representative characteristic of receptor-level processing, involving the conversion of external stimuli into neural signals by sensory receptors.
Step-by-step explanation:
The characteristic representative of receptor-level processing, not perceptual-level processing, is B. transduction. Transduction refers to the conversion of a stimulus into an electrical signal within the sensory system. This process is fundamental to how sensory receptors, such as photoreceptors in the eye or taste receptors on the tongue, convert external stimuli like light or chemicals into neural signals that can be interpreted by the brain. Spatial discrimination, on the other hand, is more related to perceptual-level processing where the brain interprets where stimuli are coming from based on the specific location of the activated receptors.