ASP.NET interview Architecture/Design questions


1) What is the difference between MVC architecture and three tier architecture?
2) What technology would you use to transfer data between two ASP.NET applications ensuring a loosely coupled architecture for the data transfer?
3) Architect a solution to ensure a record being updated in the database is locked from all users until the update is complete. How will you deal with browser closing and page change issues if the user does not complete the update?
4) How can I ensure that a method in the class is only available when it is instantiated and not when it is inherited?