Which of the following standards was introduced in 2003 and operates at 2.4 GHz with speeds of 54 Mbit/s?

The standard introduced in 2003 that operates at 2.4 GHz with speeds of 54 Mbit/s is indeed 802.11g. This Wi-Fi standard was developed to improve the data throughput of wireless networks while remaining backward compatible with 802.11b, which operated at lower speeds.

To further clarify, 802.11g achieved its maximum speed of up to 54 Mbit/s by utilizing the same 2.4 GHz frequency as 802.11b, but it employed enhancements such as Orthogonal Frequency Division Multiplexing (OFDM) for improved data transmission efficiency. This made it a popular choice for wireless networking during its time.

The other options represent different technologies: 802.11b, which was released earlier in 1999, operates at a maximum speed of 11 Mbit/s; 802.11n, introduced later in 2009, operates in both the 2.4 GHz and 5 GHz bands and can achieve far higher speeds; and 802.11ac, introduced in 2013, operates only in the 5 GHz band and provides even greater throughput than 802.11n. Each of these standards has its unique specifications and performance capabilities,