Year-wise amount of Exports from companies
| Year | Amount of exports (in crore Rs.) |
| A | B | C |
| 2012 | 40 | 90 | 70 |
| 2013 | 70 | 50 | 100 |
| 2014 | 50 | 70 | 130 |
| 2015 | 80 | 70 | 100 |
| 2016 | 110 | 90 | 70 |
| 2017 | 60 | 110 | 90 |
| 2018 | 130 | 150 | 110 |
For which of the following pairs of years, the total exports from the three companies put together are equal?