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
In proteins the α-helix and β-pleated sheet are examples of: 
Select and explain. 
A. Primary structure, B. Secondary structure, C. Tertiary structure, D. Quaternary structure
B: Secondary structure
Answer: B: Secondary structure 
Explanation: The term “secondary structure” denotes the configurational relationship between residues, which are about 3–4 amino acids apart in the linear sequence.
Reference: Vasudevan 7th  ed, pg 36