Device sensitivity in a wireless environment refers to receiver sensitivity: the minimum RF signal level a client or AP radio must receive to successfully detect, demodulate, and decode a transmission. Cisco defines receiver sensitivity as the minimum signal power level, expressed in dBm or mW, required for a receiver to accurately decode a given signal. Cisco RF design guidance further states that sensitivity indicates the lowest received power before the receiver considers the signal unintelligible.

Therefore, option A is correct because sensitivity is fundamentally about the radio’s capability to process a received signal at low power levels. A more sensitive receiver can decode weaker frames, improving effective coverage and receive performance, provided the signal-to-noise ratio and interference conditions remain acceptable. Cisco also notes that individual device sensitivity determines how well a device can hear and demodulate RF energy, which directly affects contention behavior and WLAN performance in dense environments. Redundant gateways, beacon interval synchronization, and key refresh schedules are Layer 3 availability, 802.11 timing, and security-key management topics; they do not define RF receiver sensitivity. Reference topics:RF Fundamentals — receiver sensitivity, RSSI, dBm, SNR, demodulation, and WLAN coverage behavior.