XML can be used in AJAX on client side.

[Himai Minh]

In EPractice lab, a question:

Mukyono, is a financing company located in London and Tokyo. Mykyono has legancy HP 3000 systems at both the locations, which maintains the customer and account details, and it will be updated by the Mukyono customer agencies with the help of Swing based data entry application and no other system uses these data. To support interoperability with large base of standalone client applications as possible, the services provided by Mukyono back-end application are exposed as XML based RESTful web services. Management just added a new requirement that AJAX-based web application clients be supported, too.
What would you suggest to Mukyono's new development?
Select one.
A. We can use JAX-RS to extend this application.
B. We can use Javascript and AJAX to extend this application.
C. We can use EJB based end web service points to support AJAX-based web application.

The given answer is A. EPractice lab explains :

A RESTFul web service is based on the HTTP methods and the concept of REST. It typically defines the base URI for the services, the MIME types its supports (XML, Text, JSON, user-defined) and the set of operations (POST, GET, PUT,DELETE) which are supported. JAX-RS supports the creation of the XML and JSON via JAXB.

I think the answer can be both A and C. My reason:
The question mentions that the web service is RESTFul and XML based. JAX-WS EBJ based web services can be RESTFul.
And the XML response from the service can be displayed using AJAX on the client's browsers. This reference http://www.w3schools.com/ajax/ajax_xmlfile.asp
shows us that XMLHttpRequest have a method called getElementsByTagName to retrieve XML elements and displayed using AJAX.