This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Neuro-ophthalmology, Subject name: Ophthalmology
Argyll Robeson pupil results from the lesion of 
Select and explain. 
A. Tectum region, B. Ciliary ganglion, C. Lateral geniculate body, D. Accessory ganglion
A: Tectum region
Answer: A: Tectum region 
Explanation: Argyll Robeson pupil (ARP): Here the pupil is slightly small in size and reaction to near reflex is present but light reflex is absent, i.e., there is light near dissociation (to remember, the acronym ARP may stand for 'accommodation reflex present'). It is caused by a lesion (usually neurosyphilis) in the region of tectum. Ref:- A K KHURANA; pg num:-293