The correct option is A Mid-ventral
In Dugesia, the body is flattened, thin, leaf-like and oval in outline. They exhibit bilateral symmetry and polarity is well marked. There is no well-formed head but a definite anterior end with organs of special sense is always directed forward in the direction of movement and it is broader than the other end i.e, the posterior. The mouth is situated in the mid ventral surface. Sexually mature worms have a single genital aperture situated below the mouth.