**Core Concept**
Secretory diarrhea is a type of diarrhea characterized by the excessive loss of fluids and electrolytes due to the continuous secretion of water and electrolytes into the intestinal lumen, despite the presence of a normal or even increased absorption of sodium and water. This type of diarrhea is often caused by bacterial toxins, hormonal stimulation, or certain medications that activate intestinal secretory pathways.

**Why the Correct Answer is Right**
Secretory diarrhea is usually associated with an increase in intestinal secretion, which is mediated by the activation of intestinal secretory cells, such as the crypt cells, and the release of hormones like vasoactive intestinal peptide (VIP) and secretin. The presence of a normal or increased absorption of sodium and water in secretory diarrhea is in contrast to osmotic diarrhea, where the absorption of sodium and water is impaired due to the presence of osmotically active substances.

**Why Each Wrong Option is Incorrect**
**Option A:** Not provided, skipping to Option B.
**Option B:** This option is incorrect because secretory diarrhea is characterized by the excessive loss of fluids and electrolytes, which can lead to dehydration and electrolyte imbalances.
**Option C:** This option is incorrect because secretory diarrhea is often caused by bacterial toxins, hormonal stimulation, or certain medications that activate intestinal secretory pathways, rather than an increase in intestinal motility.
**Option D:** This option is incorrect because secretory diarrhea is not typically associated with a normal or increased absorption of sodium and water, unlike osmotic diarrhea.

**Clinical Pearl / High-Yield Fact**
A key feature of secretory diarrhea is its resistance to treatment with loperamide, a medication that slows intestinal motility and can be effective in treating osmotic diarrhea.

**Correct Answer:** D.