<prompt> To contain gutta-percha within the canal, instrumentation should result in:Cleaning beyond the anatomic apexCleaning beyond the radiographic apexA cylindrical canal shapeThe narrowest cross-sectional diameter at the terminus  <response>: The instrumentation and obturation should not extend beyond the apical foramen.Whereas the guideline of 1 mm from the radiographic apex remains rational when using radiographs, the point of apical termination of the preparation and obturation remains empirical.The need to compact the gutta-percha and sealer against the apical dentin matrix constriction of the canal is necessary to prevent extrusion of materials into the periapical tissues.Textbook of Endodontics 3rd Ed P: 