Correct Option- (A) Planaria
In Planaria, true regeneration is observed, i.e., a fragmented organism regenerates the lost part of its body and develops into a new organism.
Amoeba divide by binary fission. Bacteria divide by binary fission, sporulation, transformation, conjugation and transduction. Viruses do not have cells which divide. New viruses assemble in the infected host cell and the host cell divides.