Ans.
Evolution of land plants can be defined as evolution of complex terrestrial plants, such as bryophytes, ferns, gymnosperms and angiosperms from earliest, multicellular aquatic green algae.
The early land plants were seedless plants, which produced spores for reproduction. These plants include bryophytes and pteridophytes. After some time, vascular, seeded plants were evolved into land and categorized as gymnosperms. These plants were non-flowering plants, with naked seeds.
Then, vascular, seeded plants or angiosperms were evolved, having flowers and seeds enclosed in ovary. These plants were classified as monocots and dicots on the basis of cotyledons present in seeds.
Thus, label 'A' represents 'bryophytes', 'B' represents 'gymnosperms', 'C' represents 'gymnosperms' and 'D' represents 'dicots.'
