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: Dental
The qualitative data can be presented by : 
Select and explain. 
A. Bar diagram, B. Histogram, C. Line diagram, D. Scattered Diagram
A: Bar diagram
Answer: A: Bar diagram 
Explanation: For Quantitative data:

Histogram —variables on X-axis is called "abscissa” and frequency marked on Y-axis is called  "ordinate".
Frequency polygon — indicated when sets of data to be elicited on same diagram.

Bell/normal curve is the most common type of frequency polygon. It resembles a smooth curve.

Line diagram.
Scatter/Dot/correlation diagram — shows the nature of correlation between 2 variables. If the dots cluster around a straight line, it shows a linear relationship.