<prompt> Which of the following is the national level system that provides annual national as well as state level reliable estimates of fertility and mortality?Sample registration systemCensusAd-hoc surveySample registration system  <response>: Sample Registration System SRS was initiated in 196465 on a pilot basis; full scale from 196970 to provide national as well as state level reliable estimates of fertility and mortality SRS is a dual record system:Field Investigation: continuous enumeration of births and deaths by an enumerator.Independent retrospective survey: every 6 months by an investigator-supervisor. 