This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Parasympathetic System & Glaucoma, Subject name: Pharmacology
A 28 yr old woman has been treated with several autonomic drugs for about a month. Which of the following signs would distinguish between an overdose of a muscarinic blocker and a ganglionic blocker ? 
Select and explain. 
A. Blurred vision, B. Dry mouth, constipation, C. Mydriasis, D. Postural hypotension
D: Postural hypotension
Answer: D: Postural hypotension 
Explanation: Postural hypotension is due to blockade of sympathetic system. Ganglion blockers inhibit the transmission through both sympathetic as well as parasympathetic ganglia whereas muscarinic blockers inhibit only parasympathetic activity.