On the basis of presence or absence of flowers and seeds, Eichler classified plant kingdom into two sub-kingdoms namely Cryptogamae (absence of flowers and seed; reproduction by spores) and Phanerogamae (presence of flowers and seeds). Cryptogamae was further divided into three divisions: Thallophyta, Bryophyta and Pteridophyta. Phanerogamae was further divided into two divisions: Gymnospermae (plants with naked seeds) and Angiospermae (plant with covered seeds). Thus, he divided plant kingdom into five divisions. Thus, the correct answer is option D.