Determine whether the following study is an observational study, an experiment, or a meta-analysis, and explain your choice. In a study of the effects of magnets on increasing appetite, some participants were treated with magnets while others were given non-magnetic objects a similar appearance. The magnets did not appear to be effective in increasing appetite. . . . Choose the correct answer below. A. The study is an observational study, because it is a retrospective study using data from the past. . O B. The study is a meta-analysis, because an analysis of the data was used to determine effectiveness. O C. The study is an experiment, because there is a treatment group and a control group. O D. The study is a meta-analysis, because the study was done on a group. O E. The study is an experiment, because magnets are used. OF. The study is an observational study, because the participants were observed