**Core Concept**
The question requires knowledge of luminal amoebicides, which are antiprotozoal medications used to treat amoebic infections by killing the parasites in the intestinal lumen. Effective luminal amoebicides must be able to survive the acidic environment of the stomach, be absorbed in the intestine, and then exert their effects on the amoebas.

**Why the Correct Answer is Right**
The correct answer is iodoquinol, also known as diiodohydroxyquin. Iodoquinol is a poorly absorbed drug that acts locally in the intestinal lumen, making it less effective against systemic or invasive amoebiasis. It has been shown to be effective against amoebic cysts and trophozoites in vitro, but its limited absorption and metabolism result in low systemic concentrations.

**Why Each Wrong Option is Incorrect**
**Option A:** Metronidazole is actually a more effective systemic amoebicide, targeting the trophozoites and cysts of Entamoeba histolytica in the bloodstream and tissues, rather than just the luminal environment.

**Option B:** Paromomycin is an aminoglycoside antibiotic that is used as a luminal amoebicide due to its ability to inhibit protein synthesis in amoebas. It is effective against amoebic cysts and trophozoites in the intestinal lumen.

**Option C:** Diloxanide furoate is another luminal amoebicide that is effective against Entamoeba histolytica. It works by binding to the amoebic cell membrane and disrupting its function, ultimately leading to cell death.

**Clinical Pearl / High-Yield Fact**
In treating amoebic infections, the choice of luminal amoebicide depends on the severity and location of the infection, as well as the patient's overall health and potential side effects. Localized infections may be treated with luminal amoebicides alone, while more severe cases may require systemic therapy with metronidazole.

**Correct Answer:** C. Diloxanide furoate is more effective than iodoquinol as a luminal amoebicide.