Weather forecast in the old city

There is more water in coastal areas, and the specific heat capacity of water is greater. During the day, compared with the quality of water and gravel, the absorbed heat is the same, and the temperature of water rises less.

The same heat is released at night, and the water temperature drops less, which makes the temperature difference between day and night in coastal areas smaller, so the temperature change in coastal areas is smaller, while that in inland areas is relatively larger; Old Town B is Shanghai, with large specific heat capacity based on water;

So choose D.