Assume the following:

An organizational unit has $1$ database server, $1$ application server, and $15$ clients.

The database server performs data storage and data access logic.

The application server performs business logic and the clients perform presentation logic.

Both the database and the application servers are used to address a client's request.

Question: Such a client$-$server architecture would be typically classified as:

$1-$tier architecture $($because there is only one application server in the network$).$

$2-$ tier architecture $($because there are two types of servers$).$

$3-$tier architecture $($because the database server, the application server, and the clients each form one tier respectively$).$

$n-$tier architecture, where $n=17($because there are $17$ computers in the network$).$