This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General pharmacology, Subject name: Pharmacology
Pharmacogenetics is associated with 
Select and explain. 
A. individual variations in drug response due to gene variability, B. Environmental influence, C. Individual variability in oral absorption, D. Different mechanism of actions in different individuals
A: individual variations in drug response due to gene variability
Answer: A: individual variations in drug response due to gene variability 
Explanation: The determinants of drug response, viz. transpoers, metabolizing enzymes, ion channels, receptors with their couplers and effectors are controlled genetically The study of the genetic basis for variability in drug response is called 'Pharmacogenetics'. Ref ;KD Tripathi Pharmacology 7th edition (page no;65)