N.C. Gen. Stat. § 163-213.7
The names of all candidates in the presidential preference primary shall appear at an appropriate place on the ballot or voting machine. In addition the State Board of Elections shall provide a category on the ballot or voting machine allowing voters in each political party to vote an "uncommitted" or "no preference" status. The voter shall be able to cast his ballot for one of the presidential candidates of a political party or for an "uncommitted" or "no preference" status, but shall not be permitted to vote for candidates or "uncommitted" status of a political party different from his registration. Persons registered as "Unaffiliated" shall not participate in the presidential primary except as provided in G.S.163-119.
N.C. Gen. Stat. § 163-213.7