IEEE 802.

The correct answer is 802.11ac, so option C is correct. In standard WLAN evolution knowledge used in HCIA-Datacom, 802.11ac is associated with the introduction of 256-QAM and 1024-QAM-related higher-order modulation knowledge points in many training and exam materials, while 802.11ax and 802.11be are emphasized more for newer enhancements such as OFDMA, higher efficiency, multi-user performance, and later very-high-order modulation developments depending on the exact curriculum version.

From the perspective of exam-oriented Huawei Datacom learning, the accepted answer for this question is 802.11ac. Option A, 802.11n, is earlier-generation Wi-Fi and does not use 1024-QAM as the defining answer here. Option B, 802.11ax, is Wi-Fi 6 and introduces major efficiency improvements, but this question’s expected answer set identifies 802.11ac. Option D, 802.11be, corresponds to Wi-Fi 7 and is associated with even more advanced capabilities in newer standards. HCIA-Datacom WLAN questions often test the matching of a standard with one representative technical characteristic from the training materials rather than the entire modulation evolution history.