database in C# business software

Question

Hello everyone, i am making a business oriented C# desktop software in microsoft visual studio 2010, in this  software i want to take data of applicant from online form and save that data in server database,and then that database will be retrieved and processed by my software offline,so which and how should i make database for it? like i m confused in mysql,server database,local database options provided by MS visual studio, and i have never gone through any feature of database connectivity.so can any one please help me out...