Question

what did political machines do to make sure they won elections?
they hired political cartoonists.
they committed election fraud.
they brought police forces to voting booths.
they publicized political campaigns in newspapers.

Explanation:

Political machines were known for corrupt practices. Election fraud (such as stuffing ballot boxes, intimidating voters, and using false registrations) was a common unethical method they employed to secure victories. Hiring political cartoonists or publicizing campaigns in newspapers are more legitimate political activities. Bringing police forces to voting booths might be for security in some cases but not a typical corrupt tactic of political machines compared to election fraud.

Answer:

They committed election fraud.