**Core Concept**
Amoebiasis is a parasitic infection caused by Entamoeba histolytica, which primarily affects the gastrointestinal tract. The pathogen invades the intestinal mucosa, leading to inflammation and tissue damage.

**Why the Correct Answer is Right**
The most common site for amoebiasis is the large intestine, specifically the cecum and the ascending colon. The amoebae adhere to the intestinal mucosa using a surface protein called galactose/N-acetyl-D-galactosamine (Gal/GalNAc) lectin, which interacts with host glycolipids and glycoproteins. This adherence leads to the release of proteases and other virulence factors, causing tissue destruction and inflammation.

**Why Each Wrong Option is Incorrect**
**Option A:** The small intestine is less commonly affected by amoebiasis, as the amoebae prefer the more alkaline environment of the large intestine.
**Option B:** The liver is a secondary site of infection in amoebiasis, primarily resulting from the spread of amoebae from the intestine through the bloodstream.
**Option C:** The lungs are not a primary site of infection in amoebiasis, although pulmonary amoebiasis can occur through the spread of amoebae to the lungs from the liver.

**Clinical Pearl / High-Yield Fact**
Amoebiasis can be differentiated from other causes of diarrhea by the presence of characteristic flask-shaped ulcers in the colonic mucosa during endoscopic examination.

**Correct Answer: C. The large intestine.**