The Evolutionary Tree Below Illustrates the Hypothesized Relationships Among the Six

The evolutionary tree below illustrates the hypothesized relationships among the six kingdoms and the three domains.
Many biologists have suggested revising the kingdom Protista. One current problem with the Protista, as shown in the figure, is that

A) protists are single-celled organisms and should be grouped with the bacteria or archaeans.
B) the cells of protists contain nuclei and organelles.
C) the current classification model does not reveal that plants evolved from protist ancestors.
D) the organisms currently grouped as protists do not share a recent common ancestor.