This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Preoperative assessment and monitoring in anaesthesia, Subject name: Anaesthesia
Amount of K+ in ringer lactate is 
Select and explain. 
A. 2, B. 4, C. 5, D. 6
B: 4
Answer: B: 4 
Explanation: Ringer lactate solution include a concentration of 4mEq/L.