This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Physiology
In blood, bilirubin is with 
Select and explain. 
A. Protein, B. Steroid, C. Vitamin, D. Carbohydrates
A: Protein
Answer: A: Protein 
Explanation: Bilirubin formed by the destruction of RBCs is free or unconjugated bilirubin.It is lipid soluble and bound to albumin(protein conjugation),which prevents it's excretion by the kidneys in urine. Ref.Text book of physiology by AK Jain 7th edition page no.79