Correct option is A
Explanation-
Angiosperms (flowering plants) evolved from a common ancestor, and scientists use molecular data (DNA) to determine how different groups are related and when they diverged.
The APG system is a modern classification based on phylogenetics — i.e., evolutionary relationships.
According to APG-IV, the very first groups to diverge from the common ancestor of angiosperms include:
(i) Amborellales – most basal, represented by Amborella trichopoda (only found in New Caledonia)
(ii) Nymphaeales – second most basal group (includes water lilies)
(iii) Austrobaileyales – third most basal
Together, these three form the ANA grade (Amborellales, Nymphaeales, Austrobaileyales), which represent the earliest-diverging lineages of flowering plants.
Amborellales is the most basal but not listed among the options.
Among the given options - Nymphaeales is the earliest diverging group. Other options (Monocots, Piperales, Ranunculales) are more derived and came later in angiosperm evolution.
Final answer - Option a - Nymphaeales
