You successfully run the following HTTP request.

POST https://management.azure.com/subscriptions/18c51a87-3a69-47a8-aedc-a54745f708a1/resourceGroups/RG1/providers/Microsoft.CognitiveServices/accounts/contosol/regenerateKey?api-version=2017-04-18
Body{“keyName”: “Key2”}

What is the result of the request?

A. A key for Azure Cognitive Services was generated in Azure Key Vault.

B. A new query key was generated.

C. The primary subscription key and the secondary subscription key were rotated.

D. The secondary subscription key was reset.

Explanation:
Accounts – Regenerate Key regenerates the specified account key for the specified Cognitive Services account.

Syntax:
POST https://management.azure.com/subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/providers/Microsoft.CognitiveServices/accounts/{accountName}/regenerateKey?api-version=2017-04-18

Reference:
https://docs.microsoft.com/en-us/rest/api/cognitiveservices/accountmanagement/accounts/regeneratekey