Which of these is an example of an input/event?

An input/event refers to an action or occurrence that triggers a response in a system. In this case, the user pressing a button is an example of an input/event because it is an action performed by the user that prompts a reaction or response from the app. The sound playing on the app and the code for the app are not examples of inputs/events as they do not involve an external action or occurrence that triggers a response. Therefore, the correct answer is the user presses a button.