As the print media cost increases by 10000 Euros, we see that the Volume uplift is having a poisitive and upward delta till the volume reaches 455,098 units after 455,098 volume for every 10,000 Euros the Volume in decreasing at a decreasing rate. Example:

Print Media Cost	Volume Uplift	Change in Volume	The difference in Volume for every 10000 Euros
10,000	37,235	-
20,000	86,882	86,882-37,235	49647
30,000	153,078	153,078-86,882	66196
40,000	235,824	235,824-153,078	82746
50,000	335,118	335,118-235,824	99294
60,000	455,098	455,098-335,118	119980
70,000	537,843	537,843-455,098	82745
80,000	570,941	570,941-537,843	33098
90,000	612,314	612,314-570,941	41373
100,000	637,137	637,137-612,314	24823

Based on the evaluation above, determine the optimum promotional strategy for this plan.