What is the sum of the polynomials
(8x^2-9y^2-4x)+ (x^2-3y^2-7x)

Options:
A: 7x^2-6y^2+3x
B: 9x^2-6y^2+3x
C: 9x^2-12y^2+3x
D: 9x^2-12y^2-11x