The correct option is B Enterocoelous method of coelom formation
The coelom originates by out-pouching of the archenteron during gastrulation. Each pouch then expands and its mesoderm lines the gut on the inner side and body wall on the outer side. This method of coelom formation is called as enterocoelous. It is shown by deuterostomes, such as chordates and echinoderms. Hence, option B is correct.