D. Firewall
A firewall allows the user to monitor and control network traffic, including communication between applications and the internet. By setting up firewall rules and notifications, the user can be alerted when an application tries to access the internet, giving them control over which apps are allowed to transmit data.
While operating system updates (Option A) are important for overall device security, they may not provide the real-time monitoring and control needed in this case. Remote wipe (Option B) is a feature that allows you to erase the data on a lost or stolen device but doesn't address the issue of monitoring app data usage. Antivirus (Option C) focuses on malware detection and removal but may not provide the specific feature of alerting the user about application data usage. A firewall is the most suitable solution for this specific concern.