Explanation
A common problem with many legacy devices is that they often have an identity that is composed of a single piece of information. This identity information is usually a MAC address or a serial number. Legacy devices may not have a certificate, TPM, or any other security feature that can be used to securely identify the device.
The Device Provisioning Service for IoT hub includes symmetric key attestation. Symmetric key attestation can be used to identify a device based off information like the MAC address or a serial number.
Reference:
https://docs.microsoft.com/bs-latn-ba/azure/iot-dps/how-to-legacy-device-symm-key

Explanation

Box 1: ID Scope
In the Azure portal, select the Overview blade for your Device Provisioning service and copy the ID Scope value. The ID Scope is generated by the service and guarantees uniqueness. It is immutable and used to uniquely identify the registration IDs.
Box 2: Global device endpoint
The global_prov_uri variable, which allows the IoT Hub client registration API IoTHubClient_LL_CreateFromDeviceAuth to connect with the designated Device Provisioning Service instance.
Example code:
static const char* global_prov_uri = "global.azure-devices-provisioning.net"; static const char* id_scope = "[ID Scope]"; Reference:
https://docs.microsoft.com/en-us/azure/iot-dps/tutorial-set-up-device

Use the following workflow to deploy and test your Azure Security Center for IoT security agents:
1. Enable Azure Security Center for IoT service to your IoT Hub
2. If your IoT Hub has no registered devices, Register a new device.
3. Create an azureiotsecurity security module for your devices.
Azure Security Center for IoT makes use of the module twin mechanism and maintains a security module twin named azureiotsecurity for each of your devices.
Note: To manually create a new azureiotsecurity module twin for a device use the following instructions:
1. In your IoT Hub, locate and select the device you wish to create a security module twin for.
2. Click on your device, and then on Add module identity.
3. In the Module Identity Name field, enter azureiotsecurity.
4. Click Save.
Reference:
https://docs.microsoft.com/en-us/azure/asc-for-iot/quickstart-create-security-twin

Use the following workflow to deploy and test your Azure Security Center for IoT security agents:
1. Enable Azure Security Center for IoT service to your IoT Hub
2. If your IoT Hub has no registered devices, Register a new device.
3. Create an azureiotsecurity security module for your devices.
Azure Security Center for IoT makes use of the module twin mechanism and maintains a security module twin named azureiotsecurity for each of your devices.
Note: To manually create a new azureiotsecurity module twin for a device use the following instructions:
1. In your IoT Hub, locate and select the device you wish to create a security module twin for.
2. Click on your device, and then on Add module identity.
3. In the Module Identity Name field, enter azureiotsecurity.
4. Click Save.
Reference:
https://docs.microsoft.com/en-us/azure/asc-for-iot/quickstart-create-security-twin

C: To use the file upload functionality in IoT Hub, you must first associate an Azure Storage account with your hub. Select File upload to display a list of file upload properties for the IoT hub that is being modified.
For Storage container: Use the Azure portal to select a blob container in an Azure Storage account in your current Azure subscription to associate with your IoT Hub. If necessary, you can create an Azure Storage account on the Storage accounts blade and blob container on the Containers A: IoT Hub has an endpoint specifically for devices to request a SAS URI for storage to upload a file. To start the file upload process, the device sends a POST request to {iot hub}.azure-devices.net/devices/{deviceId}/files with the following JSON body:
{
"blobName": "{name of the file for which a SAS URI will be generated}"
}
Incorrect Answers:
D: Deprecated: initialize a file upload with a GET. Use the POST method instead.
Reference:
https://github.com/MicrosoftDocs/azure-docs/blob/master/articles/iot-hub/iot-hub-configure-file-upload.md