This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Biostatistics, Subject name: Social & Preventive Medicine
Regressiom between height and age follows y=a+bx.THe curve is 
Select and explain. 
A. Hyperbola, B. Sigmoid, C. Straight line, D. Parabola
C: Straight line
Answer: C: Straight line 
Explanation: Ref:Park's Textbook of Preventive and Social Medicine 25th Ed