Oily layer of the tear film is formed by-

Ans. is 'a' i.e., Meibomian glands * The major function of lacrimal apparatus is to secrete and drain the tear. Tear film consists of 3 layersi) Mucous or mucin layer (innermost) Secreted by conjunctival goblet cells, crypts of Henle, glands of Manz.ii) Aqueous layer (intermediate) :- This forms the bulk of the tear. It is secreted by main lacrimal and accessory lacrimal glands.iii) Lipid layer (outermost) Secreted by the Meibomion, Zeis, and Moll glands.