**Core Concept**
Lithogenic bile refers to bile that has a tendency to form gallstones. This condition is often associated with an imbalance in the bile's composition, which can lead to the formation of stones. The key factor in lithogenic bile is an increased concentration of cholesterol, which is a major component of gallstones.

**Why the Correct Answer is Right**
The formation of gallstones in lithogenic bile is primarily due to an overabundance of cholesterol in the bile. When the bile contains more cholesterol than it can dissolve, it precipitates out of solution and forms stones. This process is often facilitated by an imbalance in the bile's phospholipid and bile salt content, which can also contribute to the formation of gallstones. The increased cholesterol concentration in lithogenic bile impairs the bile's ability to dissolve and transport cholesterol, leading to its precipitation and subsequent stone formation.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because while cholesterol is indeed a major component of gallstones, it is not the only factor contributing to lithogenic bile. Other factors, such as an imbalance in phospholipid and bile salt content, also play a role.
* **Option B:** This option is incorrect because phospholipid content is actually decreased in lithogenic bile, not increased. The decreased phospholipid content impairs the bile's ability to form micelles, leading to an increased concentration of cholesterol.
* **Option C:** This option is incorrect because bile salt content is actually decreased in lithogenic bile, not increased. The decreased bile salt content impairs the bile's ability to solubilize cholesterol, leading to its precipitation and subsequent stone formation.

**Clinical Pearl / High-Yield Fact**
A key clinical correlation to remember is that lithogenic bile is often associated with a diet high in cholesterol and saturated fats. A diet rich in these substances can lead to an increased concentration of cholesterol in the bile, impairing its ability to dissolve and transport cholesterol and increasing the risk of gallstone formation.

**Correct Answer: C. Phospholipid.**