Because They Are Morphologically Simple,Psilotophyta Have Traditionally Been Thought to Be

Because they are morphologically simple,Psilotophyta have traditionally been thought to be a basal group in the radiation of land plants.Molecular phylogenies have challenged this hypothesis and support the alternative hypothesis that _____.

A) they are the sister group to the seed plants
B) they represent a grade rather than a monophyletic group
C) they have lost complex structures in this lineage
D) they represent a lineage that forms a monophyletic group with Lycophyta