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
Secular trend is best demonstrated by 
Select and explain. 
A. Line diagram, B. Bar graph, C. Stem leaf plot, D. Box and whisker plot
A: Line diagram
Answer: A: Line diagram 
Explanation: Ref:Park's Textbook of Preventive and Social Medicine 25th Ed