Algae are the living cells which, have a cell wall composed of either polysaccharide (such as cellulose (a glucan)) or a variety of glycoproteins. But they are larger in size as compared to the bacterial cell.
Bacteria is a unicellular prokaryotic organism possess prominent cell wall made up of peptidoglycans.
Viroids consist solely of short strands of circular, single-stranded RNA without protein coats, it lacks a cell wall.
Mycoplasma
has
plasma membrane as the outermost covering, it lacks a cell wall. So, the correct answer is 'Bacteria'.