In post-hepatic jaundice,the concentation of conjugated bilirubin in the blood is higher than that of unconjugated bilirubin because:

• A. There is an increased rate of destruction of red blood cells
• B. The unconjugated bilirubin is trapped by the bile stone produced in the bile duct
• C. The conjugation process of bilirubin in liver remains operative without any interference
• D. The UDP-glulcuronoyltransferase activity is increased manifold in obstructive jaundice