The correct option is B can be heterotrophic.
Algae has autotrophic mode of nutrition but Euglena shows both mode of nutrition. i.e autotrophic as well as heterotrophic.
In the presence of light, Euglena can synthsise its own food as it has chloroplast. In heterotrophic mode, it surrounds the prey through a method called phagocytosis and absorbs it.