It A.

Create a scenario.

1988 - Let's make the original amount £1million tonnes
1989 - Will be £1.79 million (as it has increased by 0.79m tonnes)
1990 - Will be £2.58 million tonnes

Let's now do the percentage change between 1998 and 1989

(the difference between the two years / original amount) * 100
Therefore (0.79-1)/1 * 100 = 79% increase

Then the percentage change from 1989 to 1990.
(2.58 - 1.79) / 1.79 * 100 = 44% increase

WHY? As you can see when the denominator increases, the percentage gets smaller.