Doubling the size of an inland sea can have significant impacts on the climate of the surrounding areas. Large bodies of water generally moderate temperatures, leading to less extreme temperatures. This is due to the high specific heat capacity of water, which means it can absorb and store heat without a significant change in temperature.
When the size of an inland sea increases, it can lead to a more constant temperature in coastal areas. This is because the larger body of water will have a greater effect on the climate, mitigating the extremes of hot and cold weather.
Therefore, the most likely answer is:
B. Temperatures will be more constant.