The correct answer is option 1: Polje.

A polje is a large and flat plain that forms as a result of the dissolution of limestone or dolomite rocks. It is typically found in karst landscapes.

Let`s dissect each option to better understand why the correct answer is polje:

Option 1: Polje - A polje is the largest karst landform in terms of size. It is characterized by its large, flat plain usually surrounded by mountains or hills.

Option 2: Uvala - An uvala is a smaller karst landform that forms when two dolines merge together. Although it can be relatively large in size, it is not as large as a polje.

Option 3: Swallow Hole - A swallow hole is a karst landform where surface water disappears underground through a hole. It is much smaller in size compared to a polje.

Option 4: Sink Hole - A sinkhole is a depression or hole in the ground that forms when the underlying limestone or dolomite rocks dissolve. While it can vary in size, it is typically smaller than a polje.

In summary, the correct option is 1, polje, as it is the largest karst landform in terms of size