Which of the following causes necrotising enterocolitis

Necrotizing enterocolitis is severe and often fatal enteritis. It is caused by C.perfringens type C strains with heat resistant spores that germinate in the intestine producing beta toxin, causing mucosal necrosis. Immunization with the type C toxoid has been shown to protect against this condition. Ref: Textbook of microbiology; Ananthanarayan and paniker's; 10th Edition; Pg: 260