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
Two variables can be plotted together in ? 
Select and explain. 
A. Pie cha, B. Histogram, C. Frequency polygon, D. Scatter diagram
D: Scatter diagram
Answer: D: Scatter diagram 
Explanation: Ans. is 'd' i.e., Scatter diagram