The correct answer is: B. 50 m.
ZigBee is a low-power, mesh networking technology that is often used in wireless sensor networks. It is designed to be used in applications where battery life is a concern, such as in smart home devices. ZigBee networks can typically cover a range of up to 50 meters, but this can vary depending on the environment and the specific devices being used.
Option A is incorrect because 5 meters is too short of a range for most ZigBee applications. Option C is incorrect because 500 meters is too long of a range for most ZigBee applications. Option D is incorrect because 5 kilometers is much too long of a range for most ZigBee applications.