Which method for transmitting data is specifically designed for distances up to 30 feet?

Wi-Fi is designed for longer-range wireless networking, typically covering distances from 100 to 300 feet, depending on the specific technology and environment. Its primary function is to provide high-speed internet access and local area network connectivity, making it unsuitable for the short-range specifications of the question.

Wide area networks (WANs) are established to cover extensive geographical areas, often spanning cities, countries, or even continents. They are designed to facilitate internet connectivity and long-distance communication rather than short-range data transmission, which is not relevant to the question's criteria.

Near field communication (NFC) operates at extremely close ranges, typically within a few centimeters. While it is effective for certain applications like mobile payments, its range is significantly shorter than 30 feet, making it unsuitable for the specified distance.