Answer:
C. Z-wave
Step-by-step explanation:
The Z wave is a wireless communications protocol used primarily for automation. The Z- wave operates using a mesh network and then uses low energy radio waves to communicate from appliance to appliance.
The Z wave operates on a lower frequency than most other popular RF devices, thus making interference nonexistent.
The range of the Z-wave is 100m. Hence, it can give a perfect coverage from the base station to the company.
Option A is wrong . This is because the Zigbee is insecure and has a low coverage range (10m-20m). This means that there are possibilities of interference and also improper coverage beyond 50 m.
Option B is wrong. This is because Bluetooth devices are insecure, can loose connections under certain conditions. They have a range of 10m which is a lot lower than 50m benchmark.
Option D is wrong. NFC stands for Near Field Communication. This means its range is practically about 4cm and it cannot be used for long ranges as the company intends.