To increase security, which of the following is the BEST feature to disable on a mobile device when not in use?

"Wireless" is too broad; disabling all wireless (Wi-Fi, Bluetooth, cellular) would severely limit device functionality, and Wi-Fi/cellular are often necessary for basic operations.

GPS (Global Positioning System) primarily receives signals for location and generally poses less direct security risk than an active two-way communication protocol like NFC when idle.

"Network" is also too broad, encompassing cellular data, Wi-Fi, and other connections; disabling it would render a mobile device largely useless for its intended purpose.

NFC (Near Field Communication) allows for short-range wireless communication between devices, which can be a vector for data transfer or payment systems. Disabling NFC when not in use minimizes the risk of unintended connections, "skimming" attacks, or exploitation of potential vulnerabilities that require physical proximity to the device.