------------is a group of broadband wireless communications standards for Metropolitan Area Networks (MANs)

The IEEE 802.16 standard, commercially known as WiMAX (Worldwide Interoperability for Microwave Access), is a family of wireless broadband communication standards for Wireless Metropolitan Area Networks (WMANs). It is designed to provide wireless "last mile" broadband connectivity, serving as an alternative to cable and DSL. It can cover a radius of several kilometers, making it suitable for connecting homes and businesses in a metropolitan area to the internet.

A. 802.15 is the IEEE standard for Wireless Personal Area Networks (WPANs), such as Bluetooth, which operate over much shorter distances.
C. 802.15.4 is a specific standard within the 802.15 family for low-rate WPANs (LR-WPANs), used by protocols like Zigbee for low-power, low-data-rate applications.
D. 802.12 was a standard for 100VG-AnyLAN, a now-obsolete wired networking technology, not a wireless standard for MANs.

1. Stallings, W. (2016). Foundations of Modern Networking: SDN, NFV, QoE, IoT, and Cloud. Pearson Education, Inc. Chapter 13, Section 13.2 "IEEE 802.16 and WiMAX," describes the standard's purpose for providing broadband wireless access in a MAN.

2. IEEE Standards Association. (2012). IEEE Standard for Air Interface for Broadband Wireless Access Systems (IEEE Std 802.16-2012). The scope section (Section 1) defines the standard for fixed and mobile broadband wireless access in metropolitan networks.

3. Kurose, J. F., & Ross, K. W. (2017). Computer Networking: A Top-Down Approach (7th ed.). Pearson. Chapter 6, Section 6.3.3, discusses 802.16 WiMAX as a technology for wireless access over ranges of tens of kilometers.