Concept:Three classes that can overlap but are not subsets of one another are shown by three mutually intersecting circles.
Explanation:A person can be a son, rich, and a doctor simultaneously.
There can also be sons who are not rich or doctors, rich people who are not sons or doctors, and doctors who are not sons or rich.
So none of the classes is completely inside another.
The correct diagram must have three circles that intersect each other, with a common region.
Answer:Option D (the diagram with three mutually intersecting circles).
