Alcopar is the trade name for the drug bephenium hydroxynaphthoate. It is an antiaschelmenthic and used for the treatment of ascariasis and some other hookworm infections. Thus, the correct answer is C.

The correct answer is option 'C' - Ascariasis.

**Explanation:**

Alcopar is a drug that is commonly used in the treatment of Ascariasis. Ascariasis is a parasitic infection caused by the roundworm Ascaris lumbricoides. This infection is one of the most common helminthic infections in humans, particularly in areas with poor sanitation and hygiene.

Here is a detailed explanation of Ascariasis and the use of Alcopar in its treatment:

**1. Ascariasis:**
Ascariasis is a parasitic infection caused by the roundworm Ascaris lumbricoides. It is most prevalent in tropical and subtropical regions, where sanitation and personal hygiene are poor. The infection occurs when a person ingests the eggs of Ascaris lumbricoides, which are present in contaminated soil or food.

**2. Symptoms of Ascariasis:**
The symptoms of Ascariasis can vary depending on the severity of the infection. Common symptoms include abdominal pain, diarrhea, nausea, vomiting, weight loss, and fatigue. In severe cases, the worms can cause intestinal blockage or migrate to other organs, leading to more serious complications.

**3. Treatment of Ascariasis:**
The primary treatment for Ascariasis is the administration of anthelmintic drugs, which are medications that kill or expel parasitic worms. Alcopar is an example of an anthelmintic drug that is effective against Ascaris lumbricoides.

**4. Alcopar:**
Alcopar is the brand name for a drug called albendazole. Albendazole is a broad-spectrum anthelmintic drug that is commonly used to treat various parasitic infections, including Ascariasis. It works by inhibiting the metabolism and reproduction of the parasites, ultimately leading to their death.

**5. Mechanism of Action:**
Albendazole, the active ingredient in Alcopar, disrupts the microtubule structure in the parasite's cells. This interferes with the parasites' ability to absorb glucose, which is essential for their survival. As a result, the parasites are unable to maintain their energy levels and eventually die off. The dead parasites are then expelled from the body through the digestive system.

**6. Administration and Dosage:**
Alcopar (albendazole) is usually taken orally as a single dose. The dosage may vary depending on the severity of the infection and the patient's age and weight. It is important to follow the prescribed dosage and duration of treatment to ensure effective clearance of the parasite.

**Conclusion:**
In conclusion, Alcopar (albendazole) is a drug that is useful for the treatment of Ascariasis. Ascariasis is a parasitic infection caused by the roundworm Ascaris lumbricoides. Alcopar works by disrupting the metabolism and reproduction of the parasites, leading to their eventual death and expulsion from the body. It is important to follow the prescribed dosage and duration of treatment for effective clearance of the infection.