Which group of organisms is thought to have been the most recent common ancestor of three other kingdoms, plants, animals, and fungi?
a) archaebacteria b) eubacteria c) myxomycota d) protista

Option D is right answer that is PROTISTA.

Answer;

Protista

Explanation;Protista are eukaryotic organisms which can not be classified as a plant, animal, or fungus. Most of these organisms are unicellular, however, others such as algae are multicellular.Protists may be animal like or plant like. Examples of animal like protists include paramecium, amoebas, and plasmodium. Others such as euglena, ulva and chlamydomonas are plant-like protists.

The answer is c i just finished taking the test