Why Are Seedless Vascular Plants Considered Paraphyletic Rather Than Monophyletic

Why are seedless vascular plants considered paraphyletic rather than monophyletic?

A) Some of the groups within the seedless vascular plants are more closely related to each other than to other groups (such as Lycophyta) .
B) They share a more recent common ancestor with seeded plants than they do with the non-vascular plants.
C) All of the groups contained within the seedless vascular plants do not have the same ancestor.
D) The group includes their common ancestor but also the seeded descendants of that same ancestor.