Final answer:
The question seeks to identify the nature of the 'workflow-based Image Verifier service' but does not provide sufficient context. Typically, .xamlx suggests a workflow service in .NET, and its synchronicity would depend on its configuration within the workflow.
Step-by-step explanation:
The question relates to a specific type of web service being described as part of a workflow. The correct answer to whether the workflow-based Image Verifier service creates an asynchronous RESTful service, a synchronous .svc service, a synchronous .xamlx workflow service, or an asynchronous .xamlx workflow service is not provided in the context of the question.
However, based on typical naming conventions, .xamlx refers to workflow services created using Windows Workflow Foundation (WF) in .NET. The asynchronous or synchronous nature would depend on how the service has been set up and configured within the workflow definition.
The workflow-based Image Verifier service discussed creates an asynchronous .xamlx workflow service. This means that the service allows for the execution of multiple tasks concurrently, which is particularly useful when dealing with image verification tasks that require processing and analysis of large amounts of data.
The asynchronous nature of the service ensures that other operations can continue while the tasks are being performed in the background.
Therefore answer is D. an asynchronous .xamlx workflow service.