correction window
(2) Correction window For purposes of this subsection, the term “correction window” means the period of time beginning on the date on which the tax under subsection (a) is imposed with respect to a shortfall of distributions from a plan described in subsection (a), 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 last day of the second taxable year that begins after the end of the taxable year in which the tax under subsection (a) is imposed.