One ozone molecule contains three of oxygen.

One ozone molecule contains three atoms of oxygen.

Ozone (O3) is a triatomic molecule consisting of three oxygen atoms. Ozone is an allotropic oxygen modification that is much more unstable than the usual dual-atomic form, O2. O3 is generally present in the Earth's atmosphere: in layers of soil it is one of the most dangerous contaminants with harmful effects on the lungs; ozone in the upper layers of the atmosphere prevents the penetration of harmful ultraviolet rays to the Earth's surface.

Ithink that b is correct but just in case wait to see if someone else answers

Ithink the answer is d.