19. Which of the following are some important pollutants released by steel industry in India? 
1. Oxides of sulphur

2. Oxides of nitrogen
3. Carbon monoxide

4. Carbon dioxide

Select the correct answer using the code given below.

1. 1, 3 and 4 only

2. 1 and 3 only

3. 1 and 4 only

4. 1, 2, 3 and 4

Correct Answer :

1, 2, 3 and 4