It should be C. IMO.
C. g
Explanation:
To meet the requirements of having a rating higher than 50 Mbps and minimal range to avoid interference with other access points, the 802.11g standard is appropriate:
802.11g operates at 2.4 GHz and has a maximum theoretical speed of 54 Mbps, which meets the requirement of being higher than 50 Mbps.
802.11g also has a shorter range compared to some other standards like 802.11n and 802.11ac, which helps in minimizing interference with other access points.
Analysis of Other Options:
A. ac:
802.11ac operates primarily at 5 GHz with much higher speeds, well over 1 Gbps in ideal conditions. While it exceeds the speed requirement, its range can be longer, and it's more suited for environments needing high throughput, potentially causing more interference.
B. b:
802.11b operates at 2.4 GHz with a maximum theoretical speed of 11 Mbps, which is below the required 50 Mbps.
D. n:
802.11n can operate at both 2.4 GHz and 5 GHz, with speeds up to 600 Mbps. While it meets the speed requirement, it typically has a longer range, which might not be ideal if the goal is to avoid interference with other access points.