A una temperatura de 40c una puerta de aluminio mide

c. heat could easily travel through the molecules in the air and escape/enter the flask. removing the air slows down the heat transfer.  

c

explanation:

if the temperature drops and becomes cool

then the atmosphere can be freezing as the water vapor in the air is at maximum (100%) and can be severely cold

also can be snowing lightly as the moisture in the air will start to solidify

and btw this is not chemistry but