Which of the following is true

Options

A. All prokaryotic organisms were grouped together under Kingdom Monera
B. unicellular eukaryotic organisms were placed in Kingdom Protista
C. Kingdom Protista has brought together Chlamydomonas, Chlorella (earlier placed in Algae within Plants and both having cell walls) with Paramoecium and Amoeba (which were earlier placed in the animal kingdom which lack cell wall)
D. all of these