<prompt> All of the following may predispose to Endometrial Ca, except:Un-opposed EstrogenOral contraceptiveRadiationTamoxifen therapy  <response>: Oral contraceptives will not predispose to Endometrial Ca. Ref: Current Obs and Gynae Diagnosis and Treatment, 9th Edition, Page 916 ; Shaws Textbook of Gynaecology, 12th Edition, Pages 302-3 