Option (d) is correct

The statements A, B, and D are logically equivalent. To determine logical equivalence, we need to consider the relationship between the subject and predicate terms in each statement.

Statement A: All professors are competent scholars.

Statement B: No professors are non-competent scholars.

Statement D: All non-competent scholars are non-professors.

Statements A and B are logically equivalent because they have the same subject and predicate terms and differ only in their quantifiers ("All" and "No"). If all professors are competent scholars (A), then it follows that no professors are non-competent scholars (B), and vice versa.

Statement D is also logically equivalent to statements A and B. By stating that all non-competent scholars are non-professors, it is essentially saying that no non-professors are competent scholars.

विकल्प (d) सही है।

वेन आरेख के अनुसार, कथन A, B, और D तार्किक रूप से समानार्थी हैं।