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
The collagen triple helix structure is not found in - 
Select and explain. 
A. Cytoplasm, B. Golgi apparatus, C. Lumen of endoplasmic reticulum, D. Intracellular vesicles
A: Cytoplasm
Answer: A: Cytoplasm 
Explanation: Triple helix formation occurs in endoplasmic reticulum at procollagen level.
Triple helix of procollagen is packed into secretory intracellular vesicles in the Golgi-apparatus.
These vesicles then secrete the procollagen into extracellular space where it is converted to tropocollagen (collagen monomer).
Tropocollagens aggregate into collagen fibrils which intern become extensively cross-linked to form 'collagen fibers'.