Which statement(s) about the functions of the paranasal sinuses is/are not true?

A) They provide an extensive area of mucous epithelium.
B) They make skull bones lighter.
C) The mucus they secrete enters the oral cavities.
D) They support cilia that move the mucus.
E) They are located in the sphenoid, ethmoid, frontal, palatine and maxillae.