The correct option is B both anus and mouth are present
A digestive system is said to complete when an organism has separate openings for entry of food and exit of wastes. In animals, these openings are the mouth and the anus. This is seen from phylum Aschelmenthis to Chordata.
In an incomplete digestive system, there will be a single opening for both the entry and exit of food and wastes. Lower organisms such as flatworms have an incomplete digestive system.