Primary photoreceptor responsible for scotopic vision is:
Go with B — Rod. Within Sensory System Eye Physiology, that statement lines up with the standard definition and the usual exam wording you’ll see. In plain terms, Rod is the option that correctly names the structure, process, or principle asked for in Sensory System Eye Physiology. Holding that picture in mind makes Rod feel natural rather than something you only memorise. Link the term to a real body example (organ, tissue, or ion flow) so the idea stays concrete under exam pressure. A short mental diagram helps — start from stimulus or structure, follow the pathway, and stop at the functional result described by Rod.
Ref: Animal physiology is Unit 7 of the CSIR NET Life Science Syllabus, covering core body systems. It accounts for roughly 10% of the total marks in Sections B and C.