Is the best way to improve the heating and cooling efficiency of your home. a.) cracking windows open b.) insulation the attic and the walls c.) installing a solar panel in your kitchen d.) buying new tiles in the bathrooms

The correct option is B.
Insulating the attic and the walls will regulates the rate at which the house absorb heat from the heater and at the same time it will regulates the rate at which the heat is lost when the heater is not on. Thus, installing an insulator will help improve the heating and the cooling of the house.

The answer is !