The correct answer is: 4-)The first flowering plants were introduced toward the end of the Mesozoic era.
The first flowering plants appear about 140 million years ago (Mesozoic era is between 250 and 66 million years ago).
Flowering plants diversified extensively during the Early Cretaceous (period of Mesozoic era) and replaced conifers that were the dominant trees from 100 to 60 million years ago.