**Core Concept**
Primary bile acids are synthesized in the liver from cholesterol through a series of enzyme-catalyzed reactions. This process involves the action of the enzyme cholesterol 7-alpha-hydroxylase, which converts cholesterol into 7-alpha-hydroxycholesterol. Subsequent reactions lead to the formation of cholic acid and chenodeoxycholic acid, the two primary bile acids.

**Why the Correct Answer is Right**
The liver synthesizes primary bile acids from cholesterol through the action of the enzyme cholesterol 7-alpha-hydroxylase. This enzyme catalyzes the conversion of cholesterol into 7-alpha-hydroxycholesterol, which is then further converted into cholic acid and chenodeoxycholic acid. These primary bile acids are essential for the emulsification and absorption of dietary fats and fat-soluble vitamins in the small intestine.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not accurately describe the site of primary bile acid synthesis.
**Option B:** This option is incorrect because it does not specify the enzyme responsible for converting cholesterol into 7-alpha-hydroxycholesterol.
**Option C:** This option is incorrect because it does not accurately describe the primary bile acids synthesized in the liver.

**Clinical Pearl / High-Yield Fact**
It is essential to note that the liver also synthesizes secondary bile acids from primary bile acids through the action of intestinal bacteria. Secondary bile acids play a crucial role in maintaining colonic homeostasis and modulating the immune system.

**Correct Answer:** C. Cholic acid and chenodeoxycholic acid are the two primary bile acids synthesized in the liver.