I do not see all the graphs but it would be the reverse of what is shown for A. graph. The tickets sold to total income would have to be a 1:4 ratio where every 4 dollar leap in the y-axis is a one point (1 unit change in x).
Since the price is now 15% less you would first find what 15% of 25 is by using 25*.15 and get 3.25 then you subtract that from 25 and get 25-3.25= $21.75