Answer:
B. functional body cavity lined by tissues derived only from endoderm
Step-by-step explanation:
From the word "Pseudo" means false i.e something that is not true or literally acting in place for a particular real subject.
Coelom on the other-hand is an fluid-filled hollow cavity that act as the skeletal structure for an organism. They act helps serves as cushion effects for the organism.
Ceolomates are organism that have ceolom and the body tissues are derived from the mesodermal layer that lined the body cavity of organism possessing these ceolom.
But in pseudocoelomate they do not have a true ceolom, but there functional body cavity lined by tissues derived only from the endoderm.