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
Which of the following can prolong QT interval? 
Select and explain. 
A. Nalidixic acid, B. Ofloxacin, C. Gatifloxacin, D. Pefloxacin
C: Gatifloxacin
Answer: C: Gatifloxacin 
Explanation: Ans. is 'c' i.e, Gatifloxacin