You granted Reader access to a group of users to allow them to search service operations, such as index management and querying search data. However, users provided feedback that they are unable to perform the intended functions. 
Which action will you perform to address the concern? (Select one option)

Answer options:

A.Use API keys to grant access for content operations on the service.
B.Grant Contributor Role to the group of users through the IAM page of resource group in Azure Portal.
C.Use a Service Principal to grant access for content operations on the service.
D.Grant Owner Role to the group of users through the IAM page of resource group in Azure Portal.

Correct Answer: A
Option A is correct because the API key is the sole mechanism for authenticating inbound requests to your search service endpoint and is required on every request.
Option B is incorrect because Contributor Role provides access to create or delete the service. However, it does not grant access rights to the service endpoint. Search service operations are controlled through API keys.
Option C is incorrect because the service principal can gain access to portal resources through RBAC. Search service operations are controlled through API keys.
Option D is incorrect because the Owner Role provides access to create or delete the service. However, it does not grant access rights to the service endpoint. Search service operations are controlled through API keys.
Reference:
To learn more about authorizing access through Azure roles in Azure Cognitive Search, use the link given below: 

https://docs.microsoft.com/en-us/azure/search/search-security-api-keys