**Core Concept:**
Mucosal invasion refers to the penetration of pathogens or foreign substances into the mucosal layer of the gastrointestinal tract, particularly the intestine. Diarrheal diseases can be classified based on the underlying mechanism, such as mucosal invasion, into various types of diarrhea.

**Why the Correct Answer is Right:**
Mucosal invasion of the intestine leads to an inflammatory response, causing damage to the intestinal lining and impairing its barrier function. This results in increased permeability of the mucosa, leading to the passage of fluids and electrolytes from the intestinal lumen into the surrounding tissues and bloodstream, ultimately leading to diarrhea.

**Why Each Wrong Option is Incorrect:**
A. **Option A:** Secretory diarrhea is caused by an imbalance in electrolytes secretion, typically due to viral infections or certain medications. It does not directly result from mucosal invasion.
B. **Option B:** Mucosal invasion can lead to secretory diarrhea, but the correct answer is based on the specific type of diarrhea caused by mucosal invasion.
C. **Option C:** Osmotic diarrhea is due to an increase in the absorption of water from the intestinal lumen, which is not the result of mucosal invasion.
D. **Option D:** Transit-limited diarrhea occurs when the rate of intestinal transit is increased, which is not directly related to mucosal invasion.

**Clinical Pearl:**
Diarrhea caused by mucosal invasion is typically characterized by the presence of blood and mucus in the stool (mucopurulent diarrhea) and is often accompanied by abdominal pain, fever, and general malaise, making it more likely to be observed in infectious diseases like cholera.

**Correct Answer:** **Option D:** Transit-limited diarrhea is the correct answer, as mucosal invasion leads to an increased demand for water absorption to maintain osmotic balance within the intestine. The increased water absorption results in osmotic diarrhea, which is characterized by the excessive loss of water from the intestinal lumen, causing diarrhea.