In order to determine the effect companion animals might have on the moods of elderly people living alone experimenters created six groups from a large population of single people over 70 years old. They had three groups: those without pets, those who owned a dog, and those who owned a cat. They randomly selected 50 men from each of those groups and 50 women from each of those groups for a total of 300 participants. Which of the following statements about this study is correct? O This study is a combination of both an experiment and an observational study. O This study is an experiment, since each subject was classified into one of the six possible combinations of pet ownership and gender. O This study is an experiment, since it was based on a random sample. O This study is an observational study, since researchers did not assign the subjects to a gender or pet ownership status