The best way to solve any question from set theory is to draw a Venn Diagram.
A Venn Diagram is a pictorial representation using interlocking or overlapping circles to show the commonalities and differences between data sets.
The interlocking circles are enclosed in a big rectangle that shows the universal value.
Using a Venn Diagram helps the similarities and differences to be compared and contrasted.
Thus, when you want to solve any question from set theory, it is a good idea to draw a Venn Diagram.