Which of the following items is unique to the N-tier architecture method of designing software applications?

Which of the following items is unique to the N-tier architecture method of designing software
applications?

A.
Application layers can be separated,allowing each layer to be upgraded independently from
other layers.

B.
It is compatible with various databases including Access,Oracle,and SQL.

C.
Data security is tied into each layer and must be updated for all layers when any upgrade is
performed.

D.
Application layers can be written in C,ASP.NET,or Delphi without any performance loss.