regarding dependency of dropdownlist in asp.net c#

Question

hello sir,

 

   i am fresher.as i am doing an internship, so i am developing a web application in that i am facing a problem where i should get phone number,currency,state,city on country selection in dropdownlist(i.e every dropdownlist should have dependency).

   if possible can anyone help out me from this problem.

 

Regards,

.net FresherDeveloper