Okay, we have to consider that a clade is a group of organisms that have some criteria in common, in other words, the same evolutive trait, for example.
In this case, group C (entamoeba and slime molds) or D (diplomonads, microsporidia, and trichomonads) would be unrelated, because these organisms don't have a shared dot or origin on the cladogram. And we cannot group A (animals and plants).
So the organisms which can form a clade must be B. animals, fungi, and plants (since they have a common dot at the cladogram).