The folds in the stomach lining are called rugae. On these rugae, you will find a thin line of mucous which helps protect the stomach lining. The innermost layer is called Simple Columnar Epithelium.
She should have to classify this animal under pseudocoelomates category. The body cavity of these animals are filled with fluids. Internal organs are covered by the fluid filled space. The body cavity serves as the hydrostatic skeleton and have other functions such as digestion of food and waste removal.
Nonpoint source so your answer would be B.
