What technology does Near Field Communication (NFC) primarily use?

Near Field Communication (NFC) primarily utilizes radio waves for communication. This technology allows devices to exchange data wirelessly over very short distances, typically a few centimeters. By using radio frequency identification (RFID) principles, NFC enables simple and secure transactions, such as making payments, sharing contacts, or connecting to devices.

NFC operates within the 13.56 MHz frequency range and is designed to work in close proximity, differentiating itself from other wireless communication technologies that may operate over longer distances. This short-range characteristic is one of the reasons NFC is favored for applications where security is paramount, such as mobile payments, as it reduces the risk of interception during data transfer.

The other options do not correctly describe the technology behind NFC. Optical signals are used in technologies like QR codes but not for NFC. Electrical charges may relate to principles in capacitive touch technology, and sound frequencies pertain more to technologies like ultrasonic communication. Hence, the choice of radio waves firmly grounds NFC as a reliable and widely adopted technology in modern electronic communication.