This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anaesthesia, Subject name: Pharmacology
Which one of the following skeletal muscle relaxants causes pain on injection? 
Select and explain. 
A. Succinyl choline, B. Vecuronium, C. Rocuronium, D. Pancuronium
C: Rocuronium
Answer: C: Rocuronium 
Explanation: Rocuronium causes pain on injection. It can be minimized by alkalinizing the solution. Remember, post-operative muscular pain is caused by succinylcholine