Final answer:
The wireless data rate that uses 64-QAM and transmits over 48 subcarriers is 54 Mbps, a feature of the IEEE 802.11a/g standards for WLANs.
Step-by-step explanation:
The wireless data rate that uses 64-level Quadrature Amplitude Modulation (QAM) and transmits over 48 subcarriers is 54 Mbps (Option D). This is characteristic of the IEEE 802.11a/g standards for wireless local area networks (WLANs). In 802.11a and 802.11g networks, 64-QAM is used as one of the modulation schemes to achieve higher data rates under suitable conditions.
It's important to note that this higher data rate can only be achieved with good signal quality, as 64-QAM is more susceptible to errors than lower-level QAM schemes due to more densely packed constellation points. Modern Wi-Fi technologies, including 802.11n and 802.11ac, have continued to develop upon these modulation schemes to achieve even higher rates through the use of multiple-input and multiple-output (MIMO) antennas and wider channel bandwidths.