**Core Concept**
Levamisole is an immunomodulator that has been used in the treatment of various conditions, including cancer and autoimmune diseases. It works by **stimulating the immune system** and has **anthelmintic properties**. The underlying principle being tested involves the pharmacological effects of levamisole.

**Why the Correct Answer is Right**
Since the correct answer is not specified, let's discuss the general properties of levamisole. Levamisole can enhance **T-cell activation** and increase the production of **cytokines**, which are crucial for the immune response. It also has a role in increasing the **phagocytic activity** of neutrophils and macrophages.

**Why Each Wrong Option is Incorrect**
**Option A:** Without the specific details of option A, we cannot determine why it is incorrect.
**Option B:** Similarly, without the details of option B, its incorrectness cannot be explained.
**Option C:** The same applies to option C.
**Option D:** And option D.

**Clinical Pearl / High-Yield Fact**
A key point to remember about levamisole is its use in treating **nematode infections** and its potential to cause **agranulocytosis** as a side effect.

**Correct Answer:** Not provided in the query.