The correct option is B CH4+2O3→3CH2=O+3H2O
(1) The upper stratosphere consists of a considerable amount of ozone which protects us from the harmful UV radiation coming from the sun. The main reason for depletion is CFCs.
(2) When released in the atmosphere, CFCs mix with the normal atmospheric gases and eventually reach the stratosphere. In the stratosphere, they get broken down by powerful UV radiations, releasing chlorine free radical.
CF2Cl2(g)UV⟶∙Cl(g)+∙CF2Cl(g)
(3) The chlorine free radical ∙Cl then reacts with stratospheric ozone to form chlorine monoxide redicals Cl∙O and molecular O2.
Cl+O3(g)→Cl∙O(g)+O2(g)
Reaction of Cl∙O with atomic oxygen produces ∙Cl radicals.
Cl∙O+O(g)→∙Cl(g)+O2(g)
So, the reaction of methane with ozone doesn't happen.
Option C is correct.