The correct answer is option 3, North Sudan.

To better understand why North Sudan is not a Mediterranean country, let`s look at the other options:

1. Tunisia: Tunisia is a Mediterranean country located on the northern coast of Africa. It shares a border with the Mediterranean Sea.

2. Libya: Libya is also a Mediterranean country, located on the northern coast of Africa. It also shares a border with the Mediterranean Sea.

4. Egypt: Egypt is another Mediterranean country, located on the northeast coast of Africa. The Mediterranean Sea borders Egypt on its northern side.

Now let`s look at option 3, North Sudan: North Sudan is not a Mediterranean country. Sudan is located in northeastern Africa but does not have a coastline along the Mediterranean Sea. Therefore, it is not considered a Mediterranean country.

In summary, while Tunisia, Libya, and Egypt are all Mediterranean countries due to their coastlines along the Mediterranean Sea, North Sudan does not have this coastal access and is not considered a Mediterranean country.