The correct answer is - This research would be eligible for exemption because the researcher is not interacting with the children and the playground is a public setting. This type of research does not need IRB (IRB being institutional review board also known as ethics committee) review because the researcher will not be interacting with the children in anyway, it is purely observational and the setting is a public place, in addition all children will remain anonymous in the study, therefore the researcher is not breaking any code of ethics.