Which statement regarding $\frac{3}{N}-$tier client server architecture is fallse?

Most of the processing lagics reside in the user interface layer to speed up the server performance.

Changes in each layer are largely independent from one and ther and applications cen cuichy evalue to meet business requirements.

The same database can be shared by different application programs and different user interfaces.

Databases are not directly exposed to exiernal users. More layers of protection can be adted based on the security needs to reduce risk.