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: Biochemistry
Most basic amino acid out of the following is 
Select and explain. 
A. Alanine, B. Arginine, C. Histidine, D. Lysine
B: Arginine
Answer: B: Arginine 
Explanation: Arginine is the most basic amino acid with pk value of side chain (R) 12.5
Aspartic acid is the most acidic amino acid with pk value of side chain (R) 3.9