taxable period
(2) Taxable period The term “taxable period” means, with respect to any prohibited transaction, the period beginning with the date on which the prohibited transaction occurs and ending on the earliest of— (A) the date of mailing a notice of deficiency with respect to the tax imposed by subsection (a) under section 6212, (B) the date on which the tax imposed by subsection (a) is assessed, or (C) the date on which correction of the prohibited transaction is completed.