This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Reversible Cell Injury, Subject name: Pathology
Intracellular calcification begins in which of the following organelles? 
Select and explain. 
A. Mitochondria, B. Golgi body, C. Lysosomes, D. Nucleus
A: Mitochondria
Answer: A: Mitochondria 
Explanation: Calcium may be deposited at sites of cell death, resulting in pathologic calcification. Initiation of intracellular calcification occurs in the mitochondria of dead or dying cells that accumulate calcium.