**Core Concept**
The question tests the student's knowledge of immunosuppressant drugs and their effects on the immune system. **Immunosuppressants** are drugs that reduce the activation or efficacy of the immune system, often used to prevent rejection in organ transplant recipients.

**Why the Correct Answer is Right**
The correct answer is a drug that suppresses the immune system without having **anticancer** properties. This implies the drug does not interfere with cell division or DNA replication, which are common mechanisms of **anticancer drugs**.

**Why Each Wrong Option is Incorrect**
**Option A:** Typically has anticancer activity.
**Option B:** Often used in cancer treatment.
**Option D:** Has been shown to have effects on cell proliferation.

**Clinical Pearl / High-Yield Fact**
It's crucial to remember that not all immunosuppressants are anticancer drugs, and understanding the specific mechanisms of each is key to managing patients appropriately.

**Correct Answer:** D. Cyclosporine.