The following table shows CFC emissions (in million metric tons) from various sectors for an industry for a period of 5 years. Based on the table answer the question given below.
| Sector | ||||
| Year | Cement | Fertilizer | Foam | Pesticides |
| 2015 | 200 | 500 | 80 | 100 |
| 2016 | 300 | 600 | 90 | 110 |
| 2017 | 320 | 650 | 100 | 120 |
| 2018 | 400 | 700 | 150 | 150 |
| 2019 | 450 | 800 | 200 | 180 |
The contribution of CFC emission from the fertilizer sector, in comparison to the total CFC emissions from all the sectors, was the least in which year?
1
2017
2
2016
3
2019
4
2015