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 is observational study ?
Experiment ?
Survey ?