This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory chain, Subject name: Biochemistry
Reduction potential of potassium is 
Select and explain. 
A. -2.93, B. -0.44, C. -0.34, D. 0.54
A: -2.93
Answer: A: -2.93 
Explanation: K+ + e- = K(s) -2.93