<prompt> Plica triangularis is present inAntero-inferior pa of tonsilDorsum of tongueInlet of larynxNone  <response>: The plica triangularis is a triangular vestigeal fold of mucous membrane covering the anteroinferior pa of the tonsil. The plica semilunaris, is a similar semilunar fold that may cross the upper pa of the tonsillar sinus. Ref: BD Chaurasias HUMAN ANATOMY, Volume 3, 4th edition. 