(7x^2 + 9x + 7)(9x - 4)
= 63x^3 - 28x^2 + 81x^2 - 36x + 63x - 28
= 63x^3 + 53x^2 + 27x - 28
Therefor yes the correct answer is B :)
To solve these questions don't be afraid to just write each step out and add the like terms afterwards rather than feeling compelled to do it all in one go.