## **Core Concept**
The question tests the understanding of liver lesions and their ultrasound characteristics. The description provided - a solitary hypoechoic lesion without septa or debris - points towards a specific differential diagnosis. Ultrasound imaging is a critical tool for characterizing liver lesions.

## **Why the Correct Answer is Right**
The correct answer, **Cystic lesion/Hepatic cyst**, is the most likely diagnosis given the description. Hepatic cysts are benign lesions that appear as well-defined, hypoechoic (or anechoic) areas on ultrasound. They are usually solitary, and their appearance is characterized by the absence of internal septa or debris, which differentiates them from other types of liver lesions like abscesses or cystic neoplasms.

## **Why Each Wrong Option is Incorrect**
- **Option A:** **Hepatocellular carcinoma (HCC)** typically presents as a hypoechoic lesion but often has internal features like septa, debris, or a mosaic pattern. A simple HCC might not always show these features, but the absence of septa or debris makes it less likely compared to a cyst.
- **Option B:** **Liver metastasis** can appear hypoechoic but often has a more complex appearance, including a target or bull's eye pattern, and may have associated features like multiple lesions.
- **Option D:** **Liver abscess** usually presents with internal debris or septa, making it distinct from a simple cyst.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that simple hepatic cysts are common benign lesions that are usually asymptomatic and found incidentally. They are often anechoic (completely black) on ultrasound due to their fluid content. The presence of internal debris or septa would suggest other diagnoses like a complex cyst, abscess, or neoplasm.

## **Correct Answer:** C. Cystic lesion/Hepatic cyst