Assume the following:

An organizational unit has $1$ database server, $1$ web server, and $20$ clients.

The database server is responsible for providing data storage and data access.

The web server performs application logic $($i$.$e$.,$ business logic$).$

Each client machine performs presentation logic

Question: Assume that a client's request can be fully addressed only with the help of the web server and the database server. In other words, both the web and the database servers are necessary to address typical requests from any client machine. This network architecture would be typically classified as:

$1-$tier architecture $($because there is only one web server$)$

$2-$tier architecture $($because there are two types of servers, namely database and web servers$)$

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

$n-$tier architecture, where $n=22($because there are $22$ computers in the network$)$