The answer would be A because if you combine all the like terms you will get A as a result.
-2x^2+8x-9+4x+7x^2+2
-2x^2+7x^2 combine both of these and it will get you 5x^2
And then you would do 8x+4x which would be 12x and lastly you would -9+2 which would be -7 so the answer is A.
Hope this helps!!