In the 2.4GHz frequency band, only channels 1, 6, and 11 do not overlap with each other, providing the clearest and most interference-free channels possible in this band. Selecting one of these channels minimizes the likelihood of cross-channel interference, which is crucial in a busy office environment. Channels 3 and 9, despite being valid choices, partially overlap with other channels, potentially leading to poorer performance due to interference.