____________ valve prevents the backflow of faeces into the small intestine.

The correct option is B Ileo-caecal valve
Ileo-caecal valve is a muscular valve that prevents the backflow of faeces. It is a one-way valve present at the junction of ileum and colon. The ileum is the last part of the small intestine and the colon is the first part of the large intestine. The ileo-caecal valve allows the digested food to pass on to the colon but prevents the backflow of the faeces into the small intestine.

Sphincter of Oddi is a muscular valve that is located at the junction of the hepato - pancreatic duct. It regulates the flow of bile and pancreatic juice into the duodenum.

The pyloric sphincter is present at the junction of the pylorus of the stomach and duodenum of the small intestine. It controls the flow of food materials from the stomach to the small intestine.

The cardiac sphincter is a ring of muscles present at the upper portion of the stomach. It prevents the food from going back into the esophagus.