N.C. Gen. Stat. § 105-269.7
Any taxpayer entitled to a refund of income taxes under Article 4 of this Chapter, or any taxpayer who desires to make a contribution, may elect to contribute all or part of the refund or may make a contribution to the North Carolina Education Endowment Fund established pursuant to G.S. 115C-472.16 to be used in accordance with that statute. The Secretary shall provide appropriate language and space on the income tax form in which to make the election or contribution. The taxpayer's election or contribution becomes irrevocable upon filing the taxpayer's income tax return for the taxable year. The Secretary shall transmit the amounts designated pursuant to this section to the State Treasurer for credit to the North Carolina Education Endowment Fund.
N.C. Gen. Stat. § 105-269.7