**Core Concept**
The question tests the understanding of autonomic pharmacology, specifically the effects of muscarinic blockers and ganglionic blockers on the body. Muscarinic blockers, also known as anticholinergics, inhibit the action of acetylcholine at muscarinic receptors, while ganglionic blockers inhibit the transmission of signals in both the sympathetic and parasympathetic ganglia.

**Why the Correct Answer is Right**
Since the correct answer is not provided, let's analyze the options. An overdose of a muscarinic blocker would result in excessive inhibition of parasympathetic activity, leading to symptoms such as dry mouth, blurred vision, and constipation. On the other hand, an overdose of a ganglionic blocker would result in a loss of both sympathetic and parasympathetic tone, leading to a decrease in blood pressure and potentially life-threatening hypotension.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it is not a specific sign that can distinguish between the two types of overdoses.
**Option B:** This option is also incorrect because it does not provide a clear distinction between the effects of muscarinic blockers and ganglionic blockers.
**Option C:** This option is incorrect because it is not relevant to the specific effects of these types of drugs.
**Option D:** This option is incorrect because it does not provide a clear distinction between the effects of muscarinic blockers and ganglionic blockers.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that ganglionic blockers can cause a profound decrease in blood pressure due to the loss of sympathetic tone, whereas muscarinic blockers tend to cause more localized parasympathetic inhibition.

**Correct Answer:** Correct Answer: D. Postural hypotension is more characteristic of ganglionic blockade.