**Core Concept**
The common bile duct is a vital structure in the digestive system, responsible for transporting bile from the liver and gallbladder to the small intestine. The cell lining of the common bile duct plays a crucial role in maintaining the integrity and function of this structure.

**Why the Correct Answer is Right**
The cell lining of the common bile duct is primarily composed of **cuboidal epithelial cells**, also known as **columnar epithelial cells**. These cells have a single layer of apical microvilli, which increases the surface area for bile secretion and absorption. The cuboidal epithelial cells are responsible for the secretion of bile salts, which are essential for fat digestion and absorption in the small intestine.

**Why Each Wrong Option is Incorrect**
**Option A:** Squamous epithelial cells are typically found in areas of the body that require minimal permeability, such as the esophagus. They are not found in the common bile duct.

**Option B:** Transitional epithelial cells, also known as urothelial cells, are found in areas of the body that are subject to stretch and pressure, such as the urinary bladder. They are not found in the common bile duct.

**Option C:** Columnar epithelial cells with goblet cells are found in areas of the body that require a high degree of absorption and secretion, such as the small intestine. However, they are not the primary cell type lining the common bile duct.

**Clinical Pearl / High-Yield Fact**
The cell lining of the common bile duct is composed of cuboidal epithelial cells, which are responsible for the secretion of bile salts. This is an important consideration in the diagnosis and treatment of biliary disorders, such as cholangitis and cholestasis.

**Correct Answer:** C. Cuboidal epithelial cells.