From 'All fruit is nutritious' and 'All fruit is tasty', we know that the set of fruit is contained in both nutritious and tasty things. This means there exists an overlap between tasty and nutritious things - specifically, the fruit. Option A is incorrect because we only know that all fruit is both tasty and nutritious, not that ALL tasty things are nutritious. There could be tasty things that are not fruit and not nutritious.