If an optical scan ballot is used, the voter may use a pencil or other marking instrument provided to mark the voter's choice on the ballot.
S.D. Codified Laws § 12-18-16.1
Marking of optical scan ballot
Source: SL 2002, ch 76, § 2
Official source: South Dakota Legislature. Reproduced from public-domain South Dakota statutes; confirm against the official source for the current text. Not legal advice.