Option (b) is correct

The statements that can neither be both true nor both false are:

A. All bread is nutritious.

C. Some bread is not nutritious.

If statement A is true, then it implies that all bread is nutritious. In that case, statement C, which suggests that some bread is not nutritious, would be false.

If statement C is true, then it implies that at least some bread is not nutritious. In that case, statement A, which suggests that all bread is nutritious, would be false.

Therefore, statements A and C cannot both be true or both be false. Hence, the correct answer is option (b) A and C only.

विकल्प (b) सही है।

व्याघाती सम्बन्ध रखने वाले कथन न तो एक साथ सत्य हो सकते हैं और न ही एक साथ असत्य हो सकते हैं। कथन 'A' और 'O' के बीच तथा कथन 'I' और 'E' के बीच व्याघाती सम्बन्ध होते हैं, अतएव "सभी ब्रेड पोषक हैं" तथा कुछ ब्रेड पोषक हैं दोनों एक साथ सत्य नहीं हो सकते।