C
high specific heat capacity means water stores a lot of heat
when it is hot outside, water stores the heat, causing it to not be as hot as it could be without water
when it is cold outside, the heat from inside the water is transfered outside so that the temperature isn't as cold as it could be
so A and B are wrong (opposite)
In the case of internal temperature, the high specific heat of water should prevent variation, but I'm not too sure
