This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General physiology, Subject name: Physiology
Mitochondria have 
Select and explain. 
A. Plasmid DNA, B. Circular DNA, C. Single stranded DNA, D. Double stranded circular DNA
D: Double stranded circular DNA
Answer: D: Double stranded circular DNA 
Explanation: human mitochondrial DNA is a double-stranded circular molecule containing approximately 16,500 base pairs.(REF: GANONG'S REVIEW OF MEDICAL PHYSIOLOGY 23rd EDITION page no.34.)