The correct option is (d).
The distribution of temperature across the Earth's surface is significantly influenced by the differential heating and cooling of land and water. This phenomenon is primarily governed by the specific heat capacities of the materials involved and the mode of heat transfer (conduction vs. convection).
The temperature contrast between continents and oceans is generally greater during winter than in summer. In winter, land surfaces lose heat rapidly due to terrestrial radiation and cool down significantly, while oceans retain heat due to their high specific heat and mixing. This creates a sharp temperature difference (e.g., freezing continental interiors vs. moderate oceans). In summer, while land heats up faster than the ocean, the magnitude of the difference is usually less extreme than the cooling observed in winter. This is evidenced by the fact that isotherms (lines of equal temperature) bend more sharply at the coastlines and are more closely packed in the Northern Hemisphere during January (winter) than in July (summer).
The specific heat of water is significantly higher than that of the land surface (soil and rocks). Specific heat is the amount of energy required to raise the temperature of a unit mass of a substance by 1°C. Water requires roughly five times more heat energy to raise its temperature by the same amount as dry soil. Consequently, water heats up and cools down much more slowly than land.
Land heats and cools faster than water due to lower specific heat and opacity. However, the temperature contrast between land and sea is most pronounced during the winter season, resulting in steeper temperature gradients and stronger pressure differences.