**Core Concept**
Bilirubin is a byproduct of heme catabolism, and its conjugation and excretion are crucial for maintaining normal liver function. Inside hepatocytes, bilirubin is converted into a water-soluble compound to facilitate its excretion into the bile.

**Why the Correct Answer is Right**
Bilirubin is bound to glucuronic acid within the hepatocytes by the enzyme uridine diphosphate glucuronyltransferase (UDP-glucuronyltransferase). This conjugation reaction increases the solubility of bilirubin, allowing it to be excreted into the bile. The conjugated bilirubin is then transported to the liver canaliculi, where it is released into the bile.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to the binding of bilirubin inside hepatocytes.
**Option B:** This option is incorrect because bilirubin is not bound to albumin inside hepatocytes; it is bound to albumin in the bloodstream before being taken up by the liver.
**Option C:** This option is incorrect because bilirubin is not bound to glutathione inside hepatocytes; glutathione is involved in detoxifying various substances, including bilirubin, but not in its conjugation.

**Clinical Pearl / High-Yield Fact**
The UDP-glucuronyltransferase enzyme is responsible for the conjugation of bilirubin, and its activity is increased in conditions of bilirubin overload, such as obstructive jaundice.

**Correct Answer:** C. glutathione