The correct answer is "peritoneum". The peritoneum is a membrane that lines the abdominal cavity and covers the organs within it. It plays a crucial role in supporting and protecting the organs, as well as providing a smooth surface for them to move against. In the given options, "peritoneum" is the only term that is related to the abdominal cavity and is a correct anatomical term. The other terms mentioned, such as "periton/e", "blood", "sifted out", and "perineum", are either incorrect or unrelated to the given context.