The following table shows the production of cars in a company from 2016 to 2020.
| Years | 2016 | 2017 | 2018 | 2019 | 2020 |
| A | 30 | 23 | 39 | 25 | 18 |
| B | 16 | 10 | 14 | 12 | 8 |
| C | 15 | 18 | 19 | 25 | 30 |
| D | 31 | 12 | 21 | 19 | 20 |
There was a continuous increase in the production of cars of which type during the period 2016 ta 2020?
1
C
2
A
3
B
4
D