For this question we're looking for the option that does not explain the paradox - which is that Taychester is colder but residents spend less on heating.
A helps to explain this paradox because if the heat loss is less in Taychester than in Charlesville, then even though the temperature is warmer in Charlesville the houses might lose much more heat due to wind and therefore need to spend more on heating. Hope this helps, feel free to follow up if you still have questions!