minimum distributions for parents of 5% owners

[Guest landgcpas]

If the parent of a 5% owner becomes a plan participant at age 74 and is immediately 100% vested, when must the plan make the first required minimum distribution? For example, participation begins on 12/1/98 and the participant has an account balance as of 11/30/99. Is the first distribution made by 12/31/00 or 4/1/01?