Final answer:
Mobile push notifications are set up through the mobile app settings, where users can toggle on options to receive notifications for various events or updates.
Step-by-step explanation:
To set up mobile push notifications, the correct option would be d) Through the mobile app settings. This process typically involves going into the settings menu within the mobile application you're using and finding the section dedicated to notifications. From there, you can usually toggle on the option to receive push notifications for certain events or updates related to the app. It's also common for apps to ask for permission to send you notifications upon installation or first use.