Classify the scenarios based on whether they are observational studies, experiments, or surveys. Scenario A: Twenty employees of a company are randomly selected and asked if they would like the company to revise the existing dress code. Scenario B: Analysts at an energy research institute compare the frequency of power outages caused by snowfall in different states over the past decade. Scenario C: To determine and compare the accuracies of pedometer X and pedometer Y, researchers randomly ask consumers to use one of the two pedometers and then analyze the results. Scenario D: At a coffee shop, ten customers are randomly selected each day and asked how many times in a week they visit the shop. which ones are observational study, experimental, survey