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
Beta alanine is formed from 
Select and explain. 
A. Adenosine and thymine, B. Cytosine and Uracil, C. Cytosine alone, D. Adenosine alone
B: Cytosine and Uracil
Answer: B: Cytosine and Uracil 
Explanation: Beta alanine is formed from cytosine and Uracil.