modified adjusted gross income
(1) Limitation based on adjusted gross income The amount of the credit allowable under subsection (a) shall be reduced (but not below zero) by $50 for each $1,000 (or fraction thereof) by which the taxpayer’s modified adjusted gross income exceeds the threshold amount. For purposes of the preceding sentence, the term “modified adjusted gross income” means adjusted gross income increased by any amount excluded from gross income under section 911, 931, or 933.
26 USC § 24(b)(1)
None identified, default scope is assumed to be the parent (subpart A) of this section.