Given the function:
![f(x)=9x^7-2x^6-5x-8](https://img.qammunity.org/2023/formulas/mathematics/college/j4tbyycog9t1ngwgn35jhp23ehnrzdvipc.png)
The maximum possible number of turning points of a function is one less than the degree of the function.
This function is 7th degree function, thus the maximum possible number of turning points is:
7 - 1 = 6
Therefore, the maximun number of turning points is 6
ANSWER:
C) 6