**Core Concept**
Liver transplantation is a complex procedure that requires careful patient selection to ensure optimal outcomes. One of the key contraindications to liver transplantation is a condition that significantly increases the risk of post-transplant complications, such as infection or graft failure.

**Why the Correct Answer is Right**
The correct contraindication is a condition that makes the patient a poor candidate for immunosuppressive therapy, which is essential for preventing rejection of the transplanted liver. **Active cancer**, particularly certain types such as hepatocellular carcinoma (HCC) with vascular invasion or extrahepatic spread, is a contraindication to liver transplantation due to the high risk of recurrence and metastasis. This is because immunosuppression can facilitate the growth of cancer cells, leading to poor outcomes.

**Why Each Wrong Option is Incorrect**
**Option A:** **Hepatitis B surface antigen (HBsAg) positivity** is not a contraindication to liver transplantation. In fact, patients with HBV infection can receive a liver transplant and be treated with antiviral medications to prevent recurrence.

**Option B:** **Cirrhosis due to non-alcoholic fatty liver disease (NAFLD)** is not a contraindication to liver transplantation. Patients with NAFLD can undergo liver transplantation if they meet other selection criteria.

**Option C:** **Hepatic artery thrombosis** is a complication of liver transplantation, but it is not a contraindication to the procedure.

**Clinical Pearl / High-Yield Fact**
When evaluating a patient for liver transplantation, it is essential to consider the underlying etiology of liver disease and the patient's overall medical condition, including the presence of cancer, to determine the optimal timing and approach to transplantation.

**Correct Answer:** D.