Smog is produced due to

Answer: Option C

Smog is produced due to Smoke and fog.
Smog, or smoke fog, is a type of intense air pollution. The word "smog" was coined in the early 20^th century, and is a portmanteau of the words smoke and fog to refer to smoky fog due to its opacity and odour.
Smog is a serious problem in many cities and continues to harm human health. Ground-level ozone, sulphur dioxide, nitrogen dioxide and carbon monoxide are especially harmful to senior citizens, children, and people with heart and lung conditions such as emphysema, bronchitis, and asthma.