You are building an industrial IoT solution for a manufacturing plant equipped with a number of field devices which communicate using the MQTT protocol. Because of security and traffic monitoring reasons, you want the devices to connect to the IoT Hub via an edge device. 
How would you configure the solution for this scenario?

Answer options:

A.Create IoT Hub identity for each leaf device; Use edge as a translation gateway
B.Create IoT Hub identity for each leaf device; Use edge as a transparent gateway
C.No IoT Hub identity for the leaf devices; Use edge as a transparent gateway
D.No IoT Hub identity for the leaf devices; Use edge as a translation gateway

Correct Answer: B
Option A is incorrect because via the MQTT protocol, the leaf devices can communicate with the IoT Hub directly. No translation function is needed.
Option B is CORRECT because all the devices can communicate with the IoT Hub via MQTT. The gateway transparently mediates communication between the devices and IoT Hub while operating as a security layer.
Option C is incorrect because while the transparent gateway is the right choice for the given scenario, in case of transparent gateways, the leaf devices must have a cloud identity to be able to connect to the hub.
Option D is incorrect because the leaf devices communicate smoothly with the hub via MQTT, therefore there is no need for translation.
Diagram: 

Reference: 

https://docs.microsoft.com/en-us/azure/iot-edge/iot-edge-as-gateway?view=iotedge-2018-06#translation-gateways