This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Proteins, Subject name: Social & Preventive Medicine
Cereals are deficient in? 
Select and explain. 
A. Alanine, B. Lysine, C. Methionine, D. Cysteine
B: Lysine
Answer: B: Lysine 
Explanation: ANSWER: (B) LysineREF: Park 20th edition page 542Cereals are deficient in essential amino acid lysine, maize also being deficient in tryptophan.