SDCL § 12-18-16.1: Marking of optical scan ballot--Pen provided--Instructions--Effect.

If an optical scan ballot is used, the person in charge of the election must:

(1) Provide a black ink pen for each in-person voter to mark the voter's choice on the ballot; and

(2) Provide instructions to each voter who applies to vote by absentee ballot that the voter use a black ink pen to mark the voter's choice on the ballot.

The person in charge of the election may not disqualify any ballot marked by a writing instrument other than a black ink pen.