Okay, let's tackle this question about the drug of choice for hookworm infestation. First, I need to recall the main treatment options for helminthic infections. Hookworms are nematodes, so the first line drugs are usually anthelmintics like albendazole, mebendazole, or ivermectin. Wait, but which one is specifically recommended for hookworm?

I remember that albendazole and mebendazole are both effective against various intestinal nematodes, including hookworm. The WHO guidelines might have specific recommendations. Let me think, albendazole is often preferred because it has a broader spectrum and is used in mass drug administration programs for soil-transmitted helminths. Mebendazole is also used, but maybe the choice can depend on the region or resistance patterns. Ivermectin is more for onchocerciasis and other parasitic infections, not typically for hookworm. So the correct answer should be either albendazole or mebendazole. Which one is more specifically the drug of choice?

I think the standard treatment for hookworm is a single dose of albendazole (400 mg) or mebendazole (500 mg). Both are effective, but perhaps in some guidelines, albendazole is considered the first-line. Let me confirm: yes, the CDC and WHO recommend albendazole or mebendazole for hookworm. However, in some contexts, albendazole may be preferred due to its better bioavailability and lower cost in mass programs. So the correct answer is likely albendazole.

Now, the incorrect options. Let's consider the other drugs. Option A could be ivermectin, which isn't used for hookworm. Option B might be pyrantel pamoate, which is used for pinworms. Option C could be metronidazole, which is an antiprotozoal. Option D might be praziquantel, which is for trematodes and cestodes. So each of these is wrong because they don't target hookworm effectively.

The clinical pearl here is to remember that for soil-transmitted helminths like hookworm, the anthelmintics are albendazole and mebendazole. Also, ivermectin is not for hookworm. So the high-yield fact is that albendazole is the drug of choice.

**Core Concept**
Hookworm infestation is treated with anthelmintic drugs that target nematodes by inhibiting microtubule function, which disrupts glucose uptake and energy metabolism in the parasite. **Albendazole** and **mebendazole** are first-line agents due to their efficacy against *Ancylostoma duodenale* and *Necator americanus*, the primary hookworm species in humans.

**Why the Correct Answer is Right**
**Albendazole** is the drug of choice for hookworm infestation. It is a broad-spectrum benzimidazole that binds to β-tubulin in the worm’s microtubules, preventing polymerization and inhibiting glucose absorption. This leads to ATP depletion and death of the parasite. A single 400 mg dose is sufficient, and it is WHO-recommended for mass drug administration programs due to its efficacy, safety, and low cost. It also has activity

✓ Correct Answer: D. Albendazole