Use of Venn diagrams – UGC NET Question

Venn diagrams use overlapping circles to represent classes and their intersections. In syllogistic reasoning they visually display how subject and predicate classes relate. This makes it easier to test whether a syllogism’s conclusion follows from its premises. Therefore the method described in the stem is called a Venn diagram.

Option A:
Option A correctly identifies the overlapping circle diagrams as Venn diagrams. These diagrams provide a standard visual tool in elementary logic. Hence this option directly fits the description.

Option B:
Option B, flow chart, shows sequences of steps in a process rather than class relationships. It is commonly used in algorithm design, not in testing syllogistic validity. Thus flow chart is not the right answer here.

Option C:
Option C, network diagram, typically represents nodes and connections such as in communication or social networks. It does not conventionally illustrate logical class relations. Therefore network diagram does not match the logical use in the question.

Option D:
Option D, tree diagram, is often used to represent branching possibilities or hierarchical structures. While useful in some areas of logic, it is not the standard representation of class inclusion by overlapping regions. Hence tree diagram is not correct.