50 points! The campaign manager for one of the five candidates running for office in a city wants to conduct a survey to see how popular his candidate is among all voters in the city. He chooses the first name on a voter registration list at random then goes through the list, choosing every 15th name after that, cycling through the whole list until he ends up where he started. What type of sampling method did the campaign manager use?
A.) Non-random sampling

B.) Simple random sampling

C.) Systematic random sampling

D.) Stratified random sampling