If we credit you with a quarter of coverage (QC) for a calendar quarter under paragraph (b), (c), or (d) of § 404.141 for calendar years before 1978 or assign it to a specific calendar quarter under paragraph (b) of § 404.143 for calendar years after 1977, you acquire the QC as of the first day of the calendar quarter.
20 C.F.R. §404.145