A team of researchers evaluated a protocol designed to reduce medication errors. Data on medication errors were obtained for each month in the 12 months preceding the intervention, and for each month in the 12 months following the intervention. What type of design is this? Question 15 options: A) A nonequivalent control group pretest-posttest design B) A crossover design C) A time-series design D) A one-group pretest-posttest design