This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General Microbiology Pa-2 and Pa-3 (Sterilization and Bacterial Genetics), Subject name: Microbiology
Drug resistant in tuberculosis is due to ? 
Select and explain. 
A. Transformation, B. Transduction, C. Conjugation, D. Mutation
D: Mutation
Answer: D: Mutation 
Explanation: Drug resistance in M.tb is by Mutation in Chromosomes Metabolic defects occur as a result of mutation Eg - M.tb is normally catalase +ve INH resistant M.tb are Catalase -ve