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A) The difference in cloud cover between land and water.

B) The difference in density between land and water

C) The difference in elevation between land and water

D) The difference in specific heat capacity between land and water

The see breeze is caused by the different rate at which temperature of land and sea changes. The land mass is a better conductor of heat as compared to water. As a result during the day when sun shines the land temperature increase faster than than the sea temperature. At night when there is no sun, both land and sea cool down, but land temperature falls faster than the sea temperature. As a result the sea is cooler than land in day time, and cooler than land at night.

During the day, when land is warmer than the sea, the air above the land also becomes warmer and low air air pressure is created above land. In comparison high air pressure is created above sea, and cooler air from the sea moves towards the land. As a result during day time there is cool breeze from the sea towards the land.

During the night, when sea is warmer than the land, the air above the sea also becomes warmer and low air air pressure is created above sea. In comparison high air pressure is created above land, and cooler air from the land moves towards the sea. As a result during night time there is cool breeze from the land towards the sea.

As can be seen from this discussion, none of the options given in the question can ve considered. However. option 'B' can be considered if it is assumed that the 'density' referred there means 'air density'.

The correct answer to your question is B.  In the daytime the land surfaces become warmer than the connected water surfaces.  Due to the warmer surfaces the air over the land expands and therefore it becomes less dense. This causes the  pressure to become lower than the air pressure over the nearby water.

Because of the difference in the density of the air from land and sea, a sea breezes begin to blow toward the land from over the water.  This forces the warm air over the land to rise and cool.  Since there are no real  strong general winds, the air then flows toward the sea to replace air which has moved toward the land and this is the circulation cell.

"Sea breeze is a wind blowing from the water onto the land. Land breezes and sea breezes arise because of differential heating between land and water surfaces. Land and sea breezes can extend inland up to 100 mi (161 km) or manifest as local phenomena that quickly weaken with a few hundred yards of the shoreline. On average, the weather and cloud effects of land and sea breezes dissipate 20–30 mi (32–48 kph) inland from the coast."

By thermodynamics, the substances with lower specific heat become hotter and  quicker than the substances with  higher specific heat for the same amount of the heat they recieve.

Land has much lower specific heat than water (sea). This is the reason lthe land becomes hotter more quickly than sea wthin a few hours after sun rise. So, the surrounding air near the land  close to the sea gets hotter and lighter and goes up, causing  relatively colder air on sea rush towards the nearby land. This is a routine event during the day time causing sea breaze coming from sea towards the nearby land. So the last choice at D) is the correct cause for sea breaze.The opposite happens during  night time when land breeze rushes towards see as Land becomes cooler, more quickly than sea . The sea remains hotter and takes more time to loose heat.

By thermodynamics, the substances with lower specific heat become hotter and  quicker than the substances with  higher specific heat for the same amount of the heat they receive.    - neela

Thermodynamics is study of conversion of heat energy into work and vice versa, and how it relates to variables like pressure, volume and temperature.

Specific heat only refers to amount of heat required to raise temperature of unit mass of a substance by unit temperature. Rate of cooling and heating is dependent on conductivity of material rather than on specific heat. Thus differences in tempratures of land and sea is because of differences in conductivity rather than differences in specific heat.

Air above land is more easily warmed than air above the ocean. Warmer air rises and must be replaced by the cooler air from over the ocean.