Explanation
According to the FortiAP Configuration Guide1, "Auto TX power control allows the AP to adjust its transmit power based on the signal strength of the client. The AP will measure the signal strength of the client every 30 seconds and adjust its transmit power up or down until the client signal is detected at -70 dBm." Therefore, option A is true because it describes how the FortiAP wireless interface configures its transmission power when auto TX power control is enabled. Option B is false because FortiGate does not measure the signal strength of adjacent AP interfaces, but rather the FortiAP does. Option C is false because FortiGate does not adjust the adjacent AP power, but rather the FortiAP adjusts its own power. Option D is false becauseFortiGate does not measure the signal strength of the weakest associated client, but rather the FortiAP does.