Smog is made up of which of the following?

Smoke and fog

The correct answer is option 3. Smoke and fog

Fog-like layer is present in the atmosphere, especially during winters. This is smog which is made up of smoke and fog.

Smoke may contain oxides of nitrogen which combine with other air pollutants and fog to form smog.

The smog causes breathing difficulties such as asthma, cough and wheezing in children.