MRD amount when TEFRA election can not be produced - participant says

[JanetM]

Participant, age 76 and prior owner of Company A, says he has valid TEFRA eleciton for the Company A DB plan. He can not produce the election form. What, as plan administrator, is my responsibility when it comes to making MRD. This is a new plan for me - my company recently bought the assets of Company A and assumed sponsorship of the DB plan.