如何根据用户选择在ASPX中显示XML数据？

I have the XML given below. From this XML, in an ASPX page with an ASCX control that will contain the data, I want a drop-down on top with option "GMAT", "GRE", "LSAT", and "MCAT". And when I select GMAT below it will show only GMAT brochure and same with others.I have the XML given below. From this XML, in a