The slogan on the wall of the gas station

A, smoking will not produce oxygen, so A is wrong;

B, the gasoline at the gas station has a low ignition point, which is flammable and not provided by smoking, so B is wrong;

C, the ignition point of gasoline is certain, smoking will not increase the ignition point of gasoline, so C is wrong;

D, smoking can produce heat, make the gasoline temperature rise, reach the ignition point, so D is correct.

So choose D.