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: Pathology
The rate of bone mineralization is identical to the rate of osteoid production. The rate of newly synthesized osteoid is best estimated by: 
Select and explain. 
A. Plain X-ray, B. Tetracycline labeling, C. Alizarin red stain, D. Von kossa for calcium
B: Tetracycline labeling
Answer: B: Tetracycline labeling 
Explanation: Pulse labeling with tetracycline allows detection of rate of formation of osteoid.Two discrete tetracycline lines in tissue section separated in space can reflect the formation of bone that occurred between two oral administrations of tetracycline.The distance between the two labels can be measured and constitute the quantity of mineral deposited between those two lines during the period in which labeling did not take place. This, often referred to as the mineralization rate or calcification rate. Ref: Ohopaedic Pathology By Vincent J. Vigorita, M.D., Bernard Ghelman, M.D., Douglas Mintz, M.D., 2008, Page 106.