This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
In competetive antagonism 
Select and explain. 
A. Vmax remains same, B. Potency remains same, C. Km decreases, D. Efficacy decreases
A: Vmax remains same
Answer: A: Vmax remains same 
Explanation: Vmax corresponds to efficacy which remains same in competitive antagonism.
Km corresponds to potency and in competitive antagonism Km increases, potency decreases.