The correct answer is option 1: 3-1-4-2. Let`s analyze each option to understand how the hills should be arranged from north to south.

Option 1: 3-1-4-2

This option suggests arranging the hills in the order of Nallamala - Nilgiri - Anaimalai - Cardamom. According to this arrangement, Nallamala is the northernmost hill, followed by Nilgiri, Anaimalai, and finally Cardamom in the south.

Option 2: 4-3-1-2

This option suggests arranging the hills in the order of Anaimalai - Nallamala - Nilgiri - Cardamom. However, this is not the correct arrangement because the question asks for the arrangement from north to south.

Option 3: 1-3-4-2

This option suggests arranging the hills in the order of Nilgiri - Nallamala - Anaimalai - Cardamom. This is not the correct arrangement as it starts with Nilgiri, which is not the northernmost hill.

Option 4: 1-2-3-4

This option suggests arranging the hills in the