The correct answer is option 4: Mid-latitude cyclones are formed in regions of strong temperature contrasts.

Option 1: This statement is incorrect. Mid-latitude cyclones typically move from west to east, not from east to west. They are often referred to as "west to east storms" due to their eastward movement across the mid-latitudes of the Earth.

Option 2: This statement is incorrect. Mid-latitude cyclones can form over both land and ocean. While they are more commonly associated with the ocean, they can also develop over land regions with strong temperature contrasts.

Option 3: This statement is incorrect. Mid-latitude cyclones are known for bringing unsettled weather conditions such as clouds, precipitation, and strong winds. They rarely bring clear skies and little precipitation.

Option 4: This statement is correct. Mid-latitude cyclones form along the boundaries between warm and cold air masses, where strong temperature contrasts occur. These temperature contrasts provide the necessary energy for the development and intensification of these cyclones.