**Core Concept:** Couinaud's segmental nomenclature is a system used to divide the liver into functional and anatomic regions based on the drainage pattern of the hepatic veins. This system is widely used in clinical practice, surgery, and radiology.

**Why the Correct Answer is Right:**
Couinaud's segmental nomenclature is based on the position of the hepatic veins. The liver is divided into eight segments, each named after the dominant hepatic vein draining into it. These segments are:

1. Segment 1 (S1): Drained by the left anterior segmental vein (LAV) and the left posterior segmental vein (LPHV).
2. Segment 2 (S2): Drained by the right posterior segmental vein (RPHV) and the left posterior segmental vein (LPHV).
3. Segment 3 (S3): Drained by the right anterior segmental vein (RAV) and the right posterior segmental vein (RPHV).
4. Segment 4: Drained by the right posterior segmental vein (RPHV) and the right anterior segmental vein (RAV).
5. Segment 5: Drained by the left posterior segmental vein (LPHV) and the left anterior segmental vein (LAV).
6. Segment 6: Drained by the left posterior segmental vein (LPHV) and the left anterior segmental vein (LAV).
7. Segment 7: Drained by the right posterior segmental vein (RPHV) and the right anterior segmental vein (RAV).
8. Segment 8: Drained by the right posterior segmental vein (RPHV) and the right anterior segmental vein (RAV).

**Why Each Wrong Option is Incorrect:**
A. This option is incorrect because it refers to the Glisson's capsule, which is the fibrous connective tissue capsule surrounding the liver, rather than the hepatic veins draining into segments.
B. This option is incorrect as it refers to the portal vein system, which is related to the distribution of blood supply to the liver, not the drainage pattern of the hepatic veins.
C. This option is incorrect because it only considers the left lateral segment, which is part of Segment 5 and Segment 6, without considering the drainage patterns of the right-sided hepatic veins.
D. This option is incorrect as it only considers the right lateral segment, which is part of Segment 7 and Segment 8, without considering the drainage patterns of the left-sided hepatic veins.

**Clinical Pearls:**
The Couinaud's classification helps in understanding the anatomy of the liver and its drainage patterns, which is crucial for surgeons, radiologists, and hepatologists. This system aids in the planning of surgical procedures, liver biopsies, and diagnosis of liver lesions. Additionally, it helps in identifying the segment of the liver involved in a patient presenting with liver disease or injury, enabling appropriate treatment planning and prognosis assessment.