**Core Concept**
The question is testing the knowledge of antihelminthic drugs that have immunomodulatory effects, meaning they can modify the immune response to combat parasitic infections. **Ivermectin** is a classic example of such a drug.

**Why the Correct Answer is Right**
Ivermectin, a macrocyclic lactone, has been shown to have immunomodulatory effects by suppressing the production of pro-inflammatory cytokines, such as IL-4 and IL-13, which are involved in the pathogenesis of parasitic infections. It also increases the production of anti-inflammatory cytokines like IL-10, which helps to reduce inflammation and promote healing. Ivermectin's immunomodulatory effects are thought to be mediated through the activation of **TGF-β (Transforming Growth Factor-beta)**, which is a key regulator of immune responses.

**Why Each Wrong Option is Incorrect**
* **Option A:** Albendazole is a broad-spectrum antihelminthic, but it does not have significant immunomodulatory effects.
* **Option B:** Pyrantel is an antihelminthic that works by paralyzing the worms, but it does not have immunomodulatory effects.
* **Option C:** Mebendazole is another broad-spectrum antihelminthic, but it does not have significant immunomodulatory effects.

**Clinical Pearl / High-Yield Fact**
Ivermectin's immunomodulatory effects make it a potential therapeutic agent for various diseases, including **asthma**, **allergic rhinitis**, and **atopic dermatitis**, where dysregulation of the immune response plays a key role in their pathogenesis.

**Correct Answer:** C. Mebendazole