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: Social & Preventive Medicine
. Best for studying the decline in percentage of syphilis in men and women in last 10 years 
Select and explain. 
A. Pie chart, B. Histogram, C. Frequency polygon, D. Line diagram
D: Line diagram
Answer: D: Line diagram 
Explanation: None