<prompt> Largest opening in the Right atriumSuperior VenacavaInferior VenacavaRight Atrioventricular OrficeCoronary SInus  <response>: Right Atrioventricular Orifice Blood passes out of the right atrium through the right atrioventricular or tricuspid orifice and goes to the right ventricle. The tricuspid orifice is guarded by the tricuspid valve which maintains unidirectional flow of bloodReference: Vishram Singh Anatomy; 2nd edition; Page no: 265 