## **Core Concept**
The question pertains to the treatment of **Echinococcus granulosus**, a parasitic infection causing cystic echinococcosis or hydatid disease. This condition is characterized by the growth of parasitic cysts primarily in the liver or lungs. The management of this disease involves a combination of medical, surgical, and interventional radiology approaches.

## **Why the Correct Answer is Right**
The correct answer, **Albendazole**, is a benzimidazole derivative with broad-spectrum antiparasitic activity. It is the drug of choice for the medical treatment of cystic echinococcosis caused by **Echinococcus granulosus**. Albendazole works by inhibiting tubulin polymerization, disrupting glucose uptake, and depleting glycogen stores in the parasite, ultimately leading to its death. It is often used for inoperable cases, as an adjunct to surgery, or in cases of recurrence.

## **Why Each Wrong Option is Incorrect**
- **Option A:** Praziquantel is another antiparasitic drug but is more commonly used for schistosomiasis and infections caused by liver flukes. It is not the first-line treatment for echinococcosis.
- **Option B:** Mebendazole is also a benzimidazole derivative and has been used for treating echinococcosis, but it is less commonly used and considered less effective than albendazole.
- **Option D:** Ivermectin is primarily used for the treatment of various worm infestations, including onchocerciasis and strongyloidiasis, but it is not the treatment of choice for echinococcosis.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that for many cases of hydatid disease, especially those with accessible and uncomplicated cysts, **surgical removal** is considered the definitive treatment. However, albendazole is crucial in the medical management and can be used pre- and post-operatively to reduce the risk of recurrence.

## **Correct Answer:** B. Albendazole