Some Types of Dinoflagellates (Single-Celled Eukaryotes) Are Photosynthetic

Some types of dinoflagellates (single-celled eukaryotes) are photosynthetic. They have flagella and can swim through the water. If you grow them in a container that is lit from the right side, the cells will swim to the right side of the container. Is this an example of orientation? Why or why not?

A) No, because orientation is a type of behavior only shown by multicellular organisms.
B) No, because this is random behavior and orientation involves a directed response.
C) No, because orientation involves a response to a stimulus, and there is no stimulus in this example.
D) Yes, because there is a change in location in response to environmental information.
E) Yes, because there is movement involved, and movement always involves orientation.