**Core Concept:**
The question is asking about a disease that is characterized by a specific type of stool appearance. In this case, the characteristic Pea-soup stool is being referred to. This refers to the presence of blood-streaked stool, which can be a symptom of certain gastrointestinal conditions.

**Why the Correct Answer is Right:**
The correct answer, **Iron deficiency anaemia (IDA)**, is the right choice because it is the disease that can lead to Pea-soup stools due to the presence of blood in the stool (hemoccult positive). Iron deficiency anaemia is a common cause of anemia, characterized by reduced red blood cell count and impaired oxygen-carrying capacity. When blood is present in the stool, it is often a sign of bleeding from the gastrointestinal tract, and IDA is a common cause of this bleeding.

**Why Each Wrong Option is Incorrect:**

A. **Hemorrhoids (HP)** - While hemorrhoids can cause blood in the stool, they are not typically associated with the Pea-soup appearance. The stool color in hemorrhoids is usually bright red blood, while in IDA, the blood in the stool is mixed with the stool, giving a pea-soup color.

B. **Coeliac Disease (CD)** - Coeliac disease is a disorder caused by an immune response to gluten, leading to damage to the small intestine and malabsorption. Though CD can cause diarrhea and blood in the stool, it is not directly associated with the Pea-soup appearance. The blood in CD-related stools is typically bright red or maroon in color, while in IDA, the blood is mixed with the stool, giving a pea-soup appearance.

C. **Diverticular Disease (DD)** - Diverticular disease is a condition characterized by the formation of pouches in the colon, which can lead to inflammation, bleeding, and diarrhea. Although diverticular disease can cause blood in the stool, it does not directly result in the Pea-soup appearance. The blood in DD-related stools is typically bright red or maroon in color, while in IDA, the blood is mixed with the stool, giving a pea-soup appearance.

D. **Dysentery (DT)** - Dysentery is an inflammatory condition of the gastrointestinal tract, often caused by bacterial infections. While dysentery can result in blood in the stool, it does not directly cause the Pea-soup appearance. The blood in dysentery-related stools is typically bright red or maroon in color, while in IDA, the blood is mixed with the stool, giving a pea-soup appearance.

**Clinical Pearls:**

- IDA is a common cause of anemia, often due to blood loss from the gastrointestinal tract, leading to iron deficiency and subsequently affecting red blood cell production.
- The Pea-soup appearance of stools in IDA is a result of the mixed blood color in the stool, caused by the presence of blood mixed with the stool material.