If on any ballot the names of more persons are designated for the same office than are to be chosen, or if for any reason it is impossible to positively determine the voter's choice, all the names designated for that office shall be rejected.
A.R.S. § 16-610
Uncertainty of voter's choice as cause for rejection
Official source: Arizona State Legislature. Reproduced from public-domain Arizona statutes; confirm against the official source for the current text. Not legal advice.