As we know that the meaning of sea breeze is the cool air or wind(moving air) from above the sea when moves towards the hot land in daytime.

Actually in the daytime the land(sand) gets warmed up faster than water and so the air above land gets warmed and by warming it expands and rises up, so there becomes a low pressure area above the land , now the air above the sea is cooler and has high pressure , so it takes the place of the hot air and starts flowing towards the land and the hot air due to pressure difference created by the air above sea flows towards the sea to lower the difference.

Cooler air from sea is heavy than the hot air from land , so the (c) diagram is the most appropriate.