The plot below shows the relationship between the mortality risk of cardiovascular disease and the number of steps a person walks per day. Based on the data, which one of the following options is true?
The risk reduction on increasing the steps/day from 0 to 10000 is less than the risk reduction on increasing the steps/day from 10000 to 20000 .
The risk reduction on increasing the steps/day from 0 to 5000 is less than the risk reduction on increasing the steps/day from 15000 to 20000 .
For any 5000 increment in steps/day the largest risk reduction occurs on going from 0 to 5000 .
For any 5000 increment in steps/day the largest risk reduction occurs on going from 15000 to 20000 .