True about sphenoid sinus -
All paranasal sinuses are lined by respiratory epithelium (i.e. ciliated pseudo stratified columnar epithilium) i.e. option a is incorrect.

Sphenoid sinus: Important points

It is not present at birth
It occupies the body of sphenoid
Ostrum of sphenoid sinus is situated in the upper part of anterior wall and drains into spheno ethmoidal recess.
On x ray: Sphenoid sinus is visible by 4 years of age.
Lined by stratified squamous epithelium
Duct open in middle meatus
Open in sphenoethmoid recess
Present at birth