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
Basic amino acid (s) is/are 
Select and explain. 
A. Arginine, B. Lysine, C. Histidine, D. All of these
D: All of these
Answer: D: All of these 
Explanation: Basic amino acids → Histidine, arginine, lysine (Memonics HAL).
Acidic amino acids → Aspartic acid (aspartate), glutamic acid (glutamate).
All other 15 standard amino acids are neutral.