A store owner wants to know if he sells more water or sports drinks. He records the number of sales for both products. What is the data gathering technique used? A observational study
B voluntary survey
C randomized survey
D experiment

Due to a packaging error, 4 cans labeled diet soda were accidentally filled with regular soda and placed in a 12 pack carton of diet soda. two cans were randomly selected from this 12 pack. what is the probability that both cans were regular soda?