The common ancestor of protists was also an ancestor of many other types of eukaryotes, including fungi, plants, and animals. The evolutionary history of protists supports which of these classification schemes for protists?

A. Protists are classified together in their own kingdom and in their own clade.
B. Protists are classified together in their own kingdom, but they are not included in any clade.
C. Protists are classified in several kingdoms, but they are not included in any clade.
D. Protists are classified in several clades, some of which also contain fungi, plants, or animals.