If an employer-sponsored retirement plan includes a designated Roth account option, which of the following provisions is NOT mandatory?
A) The plan must accept rollovers from other designated Roth accounts.
B) Participants must be permitted to designate contributions to the Roth account at least annually.
C) Designated Roth account contributions must be taken into account in determining if the plan is nondiscriminatory.
D) All these provisions are mandatory.