Option (a) is correct.

Equivalent statements must have the same truth value in all situations.

Statement A says that there are no tigers that are non-mammals.

Statement B says that there are no mammals that are tigers.

These two statements are logically equivalent because they both deny the possibility of a mammal being a tiger or a tiger being a non-mammal.

Statement C says that anything that is not a mammal is not a tiger.

Statement D says that all tigers are mammals.

Statement C and D are also logically equivalent because they both assert that every tiger is a mammal and anything that is not a mammal cannot be a tiger.

Therefore, the correct answer is (a) A, C and D only.

विकल्प (a) सही है।

A. कोई भी बाघ गैर-स्तनपायी नहीं है अर्थात सारे बाघ स्तनपायी हैं।

C. सभी गैर-स्तनपायी, गैर-बाघ हैं अर्थात जो स्तनपाई नहीं हैं वे बाघ भी नहीं हैं।

D. सभी बाघ स्तनपायी हैं अर्थात सारे बाघ स्तनपायी हैं।

उपरोक्त कथन A, C और D तार्किक रूप से समतुल्य हैं।