**Core Concept**
The question tests the student's knowledge of **anticoagulant therapy** and management of **heparin-induced thrombocytopenia (HIT)**, a prothrombotic disorder. Heparin-induced thrombocytopenia is caused by an immune-mediated reaction to heparin, leading to **thrombocytopenia** and **thrombosis**.

**Why the Correct Answer is Right**
The correct answer is an anticoagulant that does not cross-react with heparin antibodies, thereby reducing the risk of worsening thrombocytopenia or thrombosis. **Argatroban** and **danaparoid** are examples of such anticoagulants, but the most commonly recommended alternative is **argatroban**, a direct **thrombin inhibitor**.

**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because it may not be the first choice for HIT.
**Option B:** Incorrect as it is not typically used for HIT.
**Option D:** Incorrect as it is not the preferred alternative to heparin in HIT.

**Clinical Pearl / High-Yield Fact**
In patients with suspected HIT, all forms of heparin should be discontinued, and an alternative anticoagulant should be initiated promptly.

**Correct Answer:** D. Argatroban.