Explanation:
To deprovision all of the devices that have been provisioned through an enrollment group:
Disable the enrollment group to disallow its signing certificate.
Use the list of provisioned devices for that enrollment group to disable or delete each device from the identity registry of its respective IoT hub.
After disabling or deleting all devices from their respective IoT hubs, you can optionally delete the enrollment group. Be aware, though, that, if you delete the enrollment group and there is an enabled enrollment group for a signing certificate higher up in the certificate chain of one or more of the devices, those devices can re-enroll.
Reference:
https://docs.microsoft.com/en-us/azure/iot-dps/how-to-unprovision-devices

1 - Obtain the group primary key
2 - Generate device SAS Keys.
3 - Flash unique credentials to the devices.
4 - Connect the devices to IoT Central
5 - Associate the devices to a template and approve the connections.
Reference:
https://docs.microsoft.com/en-us/azure/iot-central/core/concepts-get-connected
Topic 1, ADatum
Requirements
Planned Changes
ADatum is developing an Azure IoT solution to monitor environmental conditions. The IoT solution consists of hardware devices and cloud services. All the devices will communicate directly to Azure IoT Hub.
The hardware devices will be deployed to the branch offices and will collect data about various environmental conditions such as temperature, humidity, air quality, and noise level. The devices will be wired by using Power over Ethernet (PoE) connections.
ADatum is developing the solution in the following three phases: proof of value (POV), pilot, and production.
Requirements. POV Requirements
The POV phase will demonstrate that a technical solution is viable. During this phase, 100 devices will be deployed to the main office and Azure Stream Analytics will be connected to an IoT hub to generate real-time alerts. Stream Analytics will perform the following processing:
Calculate the median rate of the telemetry across the entire devices that exceed the median rate by a factor of 4.
Compare the current telemetry to the specified thresholds and issue alerts when telemetry values are out of range.
Ensure that all message content during this phase is human readable to simplify debugging.
Requirements. Pilot Requirements
During the pilot phase, devices will be deployed to 10 offices. Each office will have up to 1,000 devices.
During this phase, you will add Azure Time Series Insights in parallel to Stream Analytics to support real-time graphs and queries in a dashboard web app.
The pilot deployment must minimize operating costs.
Requirements. Production Requirements
The production phase will include all the offices.
The production deployment will have one IoT hub in each Azure region. Devices must connect to the IoT hub in their region.
The production phase must meet the following requirements:
Ensure that the IoT solution can support performance and scale targets.
Ensure that the IoT solution support up to 1,000 devices per office.
Minimize operating costs of the IoT solution.
Requirements. Technical Requirements
Datum identifies the following requirements for the planned IoT solution:
The solution must generate real-time alerts when a fire condition is detected in an office. All the devices in that office must trigger an audible alarm siren within 10 seconds of the alert.
A dashboard UI must display alerts and the system status in real time and must allow device operators to make adjustments to the system.
Each device will send hourly updates to IoT Hub. Condition alerts will be sent immediately.
Multiple types of devices will collect telemetry that has different schemas.
IoT Hub must perform message routing based on the message body.
Direct methods must be used for cloud-to-device communication.
Reports must be provided monthly, quarterly, and annually.
Stored data queries must be as efficient as possible.
The device message size will be under 4 KB.
Development effort must be minimized.
Requirements. Throttle and Quotas
The relevant throttles and quotas for various IoT Hub tiers are shown in the following table.

Requirements. IoT Hub Routing
You plan to implement IoT Hub routing during the POV phase as shown in the following exhibit.

Explanation:
Step 1: Provision Time Series Insights
Select Provision new IoT Hub to create a new IoT hub.
Step 2: Route telemetry from IoT Hub to a custom event.
Step 3: Add a data access policy to Time Series Insights for the dashboard web app Scenario: Requirements. Pilot Requirements During the pilot phase, devices will be deployed to 10 offices. Each office will have up to 1,000 devices.
During this phase, you will add Azure Time Series Insights in parallel to Stream Analytics to support real-time graphs and queries in a dashboard web app.
The pilot deployment must minimize operating costs.
Incorrect Answers:
No need to use an endpoint.
Reference:
https://docs.microsoft.com/en-us/azure/time-series-insights/time-series-insights-update-create-environment

The IoT Hub resource logs connections category emits operations and errors having to do with device connections. The following screenshot shows a diagnostic setting to route these logs to a Log Analytics workspace:

Note: Azure Monitor: Route connection events to logs:
IoT hub continuously emits resource logs for several categories of operations. To collect this log data, though, you need to create a diagnostic setting to route it to a destination where it can be analyzed or archived. One such destination is Azure Monitor Logs via a Log Analytics workspace, where you can analyze the data using Kusto queries.
Reference:
https://docs.microsoft.com/en-us/azure/iot-hub/iot-hub-troubleshoot-connectivity

B: Message enrichments is the ability of the IoT Hub to stamp messages with additional information before the messages are sent to the designated endpoint. One reason to use message enrichments is to include data that can be used to simplify downstream processing. For example, enriching device telemetry messages with a device twin tag can reduce load on customers to make device twin API calls for this information.
D: Applying enrichments
The messages can come from any data source supported by IoT Hub message routing, including the following examples:
-->device twin change notifications -- changes in the device twin device telemetry, such as temperature or pressure device life-cycle events, such as when the device is created or deleted Reference:
https://docs.microsoft.com/en-us/azure/iot-hub/iot-hub-message-enrichments-overview