In order to monitor the product quality, an enterprise takes a sample from the production line with uniform product circulation every 10 minute for testing. This sampling method is (

Test analysis: According to the definition of systematic sampling, systematic sampling is a sampling method that arranges all units in the population in a certain order, determines the sampling interval according to the sample size requirements, then randomly determines the starting point, and samples one unit every certain interval. In this question, a sample is taken from the production line with uniform product circulation every 10 minute for testing, which conforms to the nature of systematic sampling, so C is selected.