The correct option is C Ileocaecal valve
The backflow of faecal matter from the large intestine into the small intestine is prevented due to the presence of the ileocecal valve.Ileocecal valve is also called as Tulp's valve or ileal papilla. Ileocecal valve is a sphincter valve and it separates large intestine from the small intestine.
Hence, the correct answer is (C)