Read the following statements about the excretory organs of Pheretima(1) All nephridia are closed nephridia.(2) Enteronephric nephridia help in conservation of water.(3) Integumentary nephridia are absent in the first two segments.    (4) Pharyngeal nephridia are closed and enteronephric nephridia.(5) Both septal and integumentary nephridia can collect waste materials from the coelomic fluid.In the above statements how many are true ?