This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cellular Pathology, Subject name: Pathology
[{'content': 'The most-commen form of DNA variation is? \nSelect and explain. \nA. Single nucleotide polymorphism, B. Copy Number Variations (CNVs), C. Transposons, D. Mutations', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. (a) Single nucleotide polymorphism(Ref: R 9th/pg 3)Single-Nucleotide Polymorphisms (SNPs)*Variations at single nucleotide positions Q*Most prevalent Q and important form of genetic variation.*Always bi-allelic Q*Can occur in exons, introns, intergenic regions and coding regions*1 % of SNPs occur in coding regions', 'role': 'assistant'}]