The correct answer is option 4: 4 only.

Occluded fronts are created when an air mass is fully lifted above the land surface. An occluded front occurs when a cold front catches up with a warm front. This happens when a mature mid-latitude cyclone forms.

Option 1: When the front remains stationary - This does not create occluded fronts. It refers to a stationary front, which occurs when neither a cold nor warm front is advancing, and the two air masses remain stalled.

Option 2: When cold air mass moves to warm air mass - This does not create occluded fronts. It refers to a cold front, where a cold air mass advances and replaces a warm air mass.

Option 3: When warm air mass moves to cold air mass - This does not create occluded fronts. It refers to a warm front, where a warm air mass advances and replaces a cold air mass.

Option 4: When an air mass is fully lifted above the land surface - This is the correct condition for creating occluded fronts. As an air mass is lifted, the cold front catches up with the warm front, leading to the formation of an occluded front.

Therefore, only option 4 correctly describes the condition for creating occluded