You are tasked to build enhanced security around your industrial IoT infrastructure built up from PLCs and environmental sensors of a manufacturing plant. You decide to use the Azure Defender for IoT. You want to implement an enhanced security solution without intervening the configuration of the existing devices, in the shortest possible time. 
Which of the following options should you choose?

Answer options:

A.Implement an agentless solution with Defender for IoT sensors
B.Implement an agent-based solution Defender for IoT embedded security agent
C.Implement an agent-based solution with custom security agent
D.Implement Defender for IoT anomaly detection engine

Correct Answer: A
Option A is CORRECT because the Defender for IoT sensors are designed to discover and monitor network devices, without the need of any additional deployment on the devices themselves, still providing an enhanced level of security.
Option B is incorrect because while the Defender for IoT security agents allow you to build security directly into the IoT devices, application of the agent-based mode requires deployment of so-called micro agents to the devices, which doesn’t match the set requirements.
Option C is incorrect because application of the agent-based mode requires deployment of so-called micro agents to the devices. No matter what type of agent you use, it doesn’t match the requirement.
Option D is incorrect because the “anomaly detection engine” is one of the five analytics detection engines of the Defender for IoT sensors. It cannot be implemented on its own.
Reference: 

https://docs.microsoft.com/en-us/azure/defender-for-iot/resources-agent-frequently-asked-questions#do-i-have-to-install-an-embedded-security-agent