The correct option is B.
Coastal cities usually have large bodies of water around them while cities in the middle of continent have land masses surrounding them. One of the unique property of water is its relative high heat specific capacity. It takes a lot of heating before there will be significant change in the temperature of water, thus, cities around water bodies tend to experience more stable temperature. Land masses on the other hand does not absorb heat like water, thus, there is higher rate of climate fluctuation.
