This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Chemotherapy, Subject name: Pharmacology
Drug resistance transmitting factor present in bacteria 
Select and explain. 
A. Plasmid, B. Chromosome, C. Introns, D. Centromere
A: Plasmid
Answer: A: Plasmid 
Explanation: Ref KDT 6/e p671 Plasmids contain extra chromosomal DNA that help in transforming the gene responsible for multiple drug resistance among bacteria These are therefore involved in horizontal transfer not resistance