This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pigmentation, Subject name: Pathology
Brown atrophy occurs due to: 
Select and explain. 
A. Melanin, B. Hemosiderin, C. Bilirubin, D. Lipofuscin
D: Lipofuscin
Answer: D: Lipofuscin 
Explanation: Lipofuscin is an insoluble pigment,also known as Lipochrome or wear and tear pigment. -Its a sign of free radical injury and lipid peroxidation. -In sectioned tissue it appears as yellow-brown,finley granular cytoplasmic,often perinuclear pigment. -It is seen in the aging cells and is paicularly prominent in the liver and hea of aging patients. -Also seen in patients with severe malnutrition and cancer cachexia. Brown atrophy of the hea