Which rank of study design correctly shows the strong to weak causal evidence ? A、Randomized controlled experiment, single-group time series experiment, multi-group time series experiment, no control before and after comparison experiment B、Randomized controlled trial, case-control study, case-control study nested in a cohort,ecological study C、Prospective cohort study, case-control study nested in a cohort, case-control study, cross-sectional study D、Historic cohort study, prospective cohort study, case-control study, cross-sectional study